CN114614839B - A multi-channel Ka-band front-end component - Google Patents

Abstract

The invention discloses a multichannel Ka waveband front end component, which specifically comprises: the radio frequency circuit comprises four radio frequency circuits which are the same, and four intermediate frequency circuits which are the same and are formed by four intermediate frequency circuits, wherein the radio frequency circuits and the intermediate frequency circuits are connected in series in a one-to-one correspondence manner; the self-checking one-to-four power distribution network is respectively connected to the coupling ends of the couplers in the four-path radio frequency circuit, so that the self-checking function of the component is realized; the local oscillator one-to-four power distribution network is respectively connected to local oscillator ends of the frequency mixers in the four-path radio frequency circuit to provide local oscillator signals required by component frequency mixing. According to the Ka-band front-end component, a millimeter-wave broadband frequency mixing technology is adopted, millimeter-wave band signals are mixed to a low-frequency band, a noise baseline is more stable by adopting an SDLVA technology, a temperature compensation attenuator and a baseline compensation unit are added, and the influence of temperature on the performance of the component is reduced; the interior of the component adopts the micro-assembly and electric fitting mixed assembly process, and the component has the characteristics of high sensitivity, large dynamic, stable full-temperature characteristic, small volume, low assembly requirement and the like.

Description

A multi-channel Ka-band front-end component

technical field

The invention belongs to the field of microwave and millimeter wave technology, and in particular relates to a multi-channel Ka-band front-end component.

Background technique

With the application of modern radar technology, electronic countermeasures will face a more complex and changeable electromagnetic environment. Due to its frequency band characteristics, millimeter waves have been widely used in precision-guided weapons and various aircraft systems. In a complex electromagnetic environment, it is a very complicated and arduous task to sort out various external radiations for analysis and identification, and to give an accurate alarm. As one of the basic direction finding technologies, the amplitude direction finding technology has a higher intercept probability than the phase direction finding in the azimuth dimension. At the same time, it can be widened in the frequency domain, the instantaneous bandwidth is very wide, the equipment is relatively simple, and it is easy to transplant to various platforms. It has been widely used in modern reconnaissance and alarm equipment. As the front-end of the millimeter-wave ratio-amplitude direction-finding system, the traditional Ka-band front-end components usually use a coaxial detector, which is bulky and unfavorable for integration. The linear dynamic range is small, only about 35dB, and cannot be expanded.

Contents of the invention

The purpose of the present invention is to provide a multi-channel Ka-band front-end component with high integration, high sensitivity and wide linear dynamic range.

The specific technical solution of the present invention is: a multi-channel Ka-band front-end component, including four radio frequency circuits, four intermediate frequency circuits, a self-inspection one-point four-power distribution network and a local oscillator one-point four-power distribution network, wherein:

The four radio frequency circuits are composed of four identical radio frequency circuits, the four intermediate frequency circuits are composed of four identical intermediate frequency circuits, and the radio frequency circuits and the intermediate frequency circuits are connected in series in one-to-one correspondence;

The self-checking one-point four-power splitting network is respectively connected to the coupling end of the coupler in the four-way radio frequency circuit to realize the self-checking function of the component;

The one-to-four power-splitting network of the local oscillator is respectively connected to the local oscillator end of the mixer in the four-way radio frequency circuit to provide the local oscillator signal required for component mixing.

Beneficial effects of the present invention: (1) Continuous logarithmic detection and amplification is carried out after the Ka-band signal is mixed to the low frequency band, which is more convenient for integration; (2) While having extremely high sensitivity, it also has a very wide instantaneous linear dynamic range, And the linear dynamic range can be expanded; (3) Built-in temperature compensation attenuator and baseline compensation unit, the indicators are relatively stable under full temperature conditions; (4) The components adopt a mixed assembly process of micro-assembly and electric assembly, which takes up space Reduced by more than 50%, high integration, and low requirements for assembly.

Description of drawings

FIG. 1 is a schematic diagram of the principle of a multi-channel Ka-band front-end component according to an embodiment of the present invention.

Fig. 2 is a schematic diagram of the principle of a temperature-compensated attenuator according to an embodiment of the present invention.

Fig. 3 is a schematic diagram of the principle of a self-inspection one-point four-power-division network according to an embodiment of the present invention.

Fig. 4 is a schematic diagram of the principle of a local oscillator one-point four-power-division network according to an embodiment of the present invention.

FIG. 5 is a schematic diagram of assembly of a multi-channel Ka-band front-end assembly according to an embodiment of the present invention.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

As shown in Figure 1, the multi-channel Ka-band front-end assembly of the present invention includes four radio frequency circuits, four intermediate frequency circuits, a self-checking one-point four-power distribution network and a local oscillator one-point four-power distribution network, wherein:

The four radio frequency circuits are composed of four identical radio frequency circuits, the four intermediate frequency circuits are composed of four identical intermediate frequency circuits, and the radio frequency circuits and the intermediate frequency circuits are connected in series in one-to-one correspondence;

The self-checking one-point four-power splitting network is respectively connected to the coupling end of the coupler in the four-way radio frequency circuit to realize the self-checking function of the component;

The one-to-four power-splitting network of the local oscillator is respectively connected to the local oscillator end of the mixer in the four-way radio frequency circuit to provide the local oscillator signal required for component mixing.

The details of each part are as follows:

(1) The four radio frequency circuits are composed of four identical radio frequency circuits, and each radio frequency circuit is composed of a coupler CP1, a single-pole double-throw switch SW1, an amplifier AM1, a fixed attenuator AT1, a single-pole double-throw switch SW2, and a radio frequency band-pass filter BP1, digital control attenuator AT2 and mixer MX1 are cascaded, and the working frequency is 30-40GHz.

In this embodiment, the coupler CP1 adopts a microstrip parallel coupling structure, and the coupling port is connected to a self-inspection one-point four-power distribution network. The coupling degree is usually about 20dB, and the insertion loss is within 0.3dB, so as to realize the self-inspection function of the component (check the channel work properly).

The SPDT switch SW1 and the SPDT switch SW2 belong to the same type of MMIC device, and are composed of PIN tubes based on AlGaAs technology. They have small insertion loss (no more than 0.6dB) in the entire Ka-band to ensure the reliability of the components. Sensitivity; higher input P-1 to ensure the dynamic range of components; smaller rising and falling edges, within 15ns.

In this embodiment, the amplifier AM1 is formed by cascading a GaAs MMIC low-noise amplifier and a three-stage self-biased broadband low-noise amplifier, powered by +4.5V, the noise figure of the entire Ka-band is within 3dB, and the gain is about 20dB. Noise figure and high gain to improve the receiving sensitivity of the front-end components, which help to increase the detection range of the amplitude direction finding system.

The fixed attenuator AT1 adopts MMIC fixed attenuator based on GaAs process, which is composed of thin film resistors, and has extremely flat attenuation and small input and output return loss in the entire working bandwidth.

In this embodiment, SPDT switches SW1 and SW2, amplifier AM1 and fixed attenuator AT1 form a simple linear dynamic expansion circuit. When a small signal smaller than the set threshold enters the channel, the SPDT switch SW1 and SPDT switch SW2, so that the small signal is output through SPDT switch SW1, amplifier AM1 and SPDT switch SW2; when a large signal greater than the set threshold enters the channel, the SPDT switch SW1 and SPDT are controlled by control The double-throw switch SW2 makes the large signal output through the single-pole double-throw switch SW1, the fixed attenuator AT1 and the single-pole double-throw switch SW2, so that the components always work in a linear working state and achieve the purpose of linear dynamic scalability. The fixed attenuator AT1 The attenuation value is jointly determined by the gain of the amplifier AM1 and the linear dynamic expansion requirement.

In this embodiment, the RF bandpass filter BP1 adopts a three-wire microstrip structure and is integrated with the microstrip signal transmission line. The plate material Rogers 5580 is selected, and the near-end suppression is high, and the insertion loss in the passband 30-40GHz is less than 1dB , the standing wave is not greater than 1.6, the suppression of DC-24GHz is above 65dBc, and the suppression of 42GHz~48GHz is above 40dBc; it mainly suppresses the possible interference signals outside the RF working bandwidth (30-40GHz), especially the image frequency and One-half frequency division of the RF operating frequency.

In this embodiment, the numerically controlled attenuator AT2 is a 2-bit numerically controlled attenuator integrated with GaAs MMIC, the frequency range covers 30-40GHz, the insertion loss is ≤4dB, and the step is 10dB. It adopts TTL logic control, and the switching speed is less than 20ns. Better input and output VSWR, improving internode matching between mixer MX1 and RF link.

The numerically controlled attenuator AT2 performs step-by-step attenuation according to requirements. When a small signal smaller than the set threshold enters the channel, the numerically controlled attenuator AT2 does not attenuate; when a large signal greater than the set threshold enters the channel, if the subsequent device works in a non-linear state, the digitally controlled attenuator AT2 will attenuate in accordance with 10dB, 20dB, 30dB and 40dB in sequence, so that the subsequent devices will always work in the linear working state and achieve the purpose of further expanding the linear dynamic range.

In this embodiment, the mixer MX1 adopts a passive double-balanced MMIC mixer, which has extremely low insertion loss in the passband, high isolation between ports, high spurious suppression, and high input P- 1. The working frequency of radio frequency and local oscillator covers 20-40GHz, and the working frequency of intermediate frequency covers DC-18GHz. There is a high isolation between the three ports, especially the isolation between the local oscillator and the radio frequency port is above 40dB; passband interpolation The loss does not exceed 10dB, the fluctuation does not exceed 3dB, and the input P-1 is not less than 5dBm.

The local oscillator port of the mixer MX1 is connected to the local oscillator's one-point four-power distribution network to down-convert the RF signal to the intermediate frequency; each port needs to meet the corresponding working frequency band, and the ports have a certain degree of isolation, and can control the intermediate frequency after mixing. The spurious signals generated within the bandwidth have a certain degree of suppression.

(2) The four-way intermediate frequency circuit is composed of four identical intermediate frequency circuits, each of which has the same circuit structure, including the intermediate frequency band-pass filter BP2, the temperature compensation attenuator AT3, the power divider PW1, and the power divider set in series. One output of the device PW1 is sequentially connected to the continuous logarithmic detection amplifier (SDLVA) SA1 and the baseline compensation circuit BL1, and the other output is sequentially connected to the fine-step numerical control attenuator AT4 and the output of the amplifier AM2. The working frequency of the intermediate frequency circuit is 6-16 GHz;

In this embodiment, the intermediate frequency bandpass filter BP2 adopts a microstrip cochin structure. Since the intermediate frequency frequency of 6-16 GHz is lower than that of the RF frequency, the plate material is ceramic AL2O3, and the filter is small in size and can be bonded, gold wire The bonding method is integrated with the external microstrip signal transmission line, the passband is as narrow as possible, the insertion loss in the passband is not greater than 4dB, and the sideband suppression reaches more than 30dB at 1GHz; the passband of the intermediate frequency bandpass filter BP2 meets the requirements of the intermediate frequency bandwidth The premise should be as narrow as possible to reduce the spurious signals entering the SDLVA and improve the sensitivity of the SDLVA. The intermediate frequency bandpass filter BP2 mainly suppresses possible stray signals outside the intermediate frequency bandwidth, especially the local oscillator frequency and its half-frequency division.

As shown in Figure 2, in this embodiment, the temperature compensation attenuator AT3 is composed of an external temperature sensor, a single-chip microcomputer and a digital-to-analog converter. The details are as follows:

The electronically adjustable attenuator adopts GaAs MMIC electronically adjustable chip, its frequency range covers DC-20GHz, the insertion loss is not more than 3dB, the attenuation range is 0-10dB, and the response speed is less than 20ns.

The temperature sensor works at -40℃～+125℃, has extremely low self-heating, and converts the ambient temperature into a digital signal output.

The digital-to-analog converter has a high resolution, no less than 12 bits, a stabilization time of no more than 4.5us, a built-in voltage reference source, and a double-buffer register.

The temperature sensor collects the ambient temperature and converts it into a digital signal. The digital signal is converted into an analog signal by a digital-to-analog converter after being processed by a single-chip microcomputer. The analog signal drives the ESC attenuator to change the attenuation, thereby achieving the purpose of temperature compensation. Temperature compensation attenuation AT3 can adjust the attenuation of the electronically adjustable attenuator by writing a single-chip program, improve the consistency between each video output (Video Out) channel, and help improve the accuracy of the direction finding system.

In this embodiment, the power divider PW1 adopts GaAs MMIC 0° two-way power divider, the frequency covers 2-18GHz, the insertion loss is not higher than 4.5dB, and the isolation is better than 12dB.

In this embodiment, the continuous logarithmic detection amplifier SA1 has a working frequency range of 0.5-18 GHz, an in-band flatness of ±2 dB, a rising edge of 5 ns and a falling edge of 15 ns for the pulse detection output, a delay of no more than 10 ns, and a recovery time of less than 10 ns. Over 40ns, logarithmic slope 15mV/dB, detection dynamic range 67dB.

Continuous logarithmic detection amplifier SA1 converts microwave radio frequency signals into video signal output. The working bandwidth needs to include the intermediate frequency bandwidth and has good frequency flatness. The pulse detection has extremely fast rising and falling edges and meets the requirements of front-end components. The required recovery time is usually on the order of nanoseconds.

Continuous logarithmic detection amplifier SA1, because of its detection principle, the clutter signal may interfere with the final video signal, mainly manifested as the jitter of the video signal output by the detection, which affects the working sensitivity and linear dynamic range of the amplitude ratio direction finding system , so it is necessary to analyze the impact of spurious signals and harmonic signals in the working bandwidth on the detection before confirming the specific frequency conversion scheme (that is, the frequency of the local oscillator signal).

Specifically: when the difference between the spurious signal and the main signal is more than 100MHz, the influence can be ignored; when the spurious signal is close to the main signal, and the suppression of the spurious signal reaches 40dBc, the influence can be ignored. From this, the frequency mixing scheme can be determined, and the frequency of the local oscillator signal is 24 GHz.

Continuous logarithmic detection amplifier SA1, the detection range is 15dB higher than the instantaneous linear dynamic range required by the front-end components, in order to improve the receiving sensitivity of the front-end components and reduce the impact of frequency flatness in the working bandwidth; according to the detection range of SA1 The noise figure and gain requirements of the component can be determined.

In this embodiment, the baseline compensation circuit BL1 includes a temperature sensor, a voltage bias circuit and an operational amplifier OA1. The SDLVA output video signal is connected to the "+" input terminal of OA1, and the temperature sensor and voltage bias circuit are connected to the "+" input terminal of OA1. -" input, the voltage bias circuit is mainly used to offset the baseline drift caused by SDLVA's own noise, RF circuit and intermediate frequency circuit noise, and the temperature sensor is mainly used to offset the change of circuit noise with temperature changes.

The temperature sensor can work at -40°C ~ +125°C, has extremely low self-heating, and can convert the ambient temperature into an analog signal output; the voltage bias circuit is composed of a precision power supply and a resistor in series. The initial value of the voltage is selected as the noise level of the continuous logarithmic detection amplifier SA1; the operational amplifier OA1 is a low-noise, high-speed current feedback amplifier, and its 3dB bandwidth reaches 95MHz (with a power supply of ±5V and a gain of 1dB). The slew rate reaches 820V/us (power supply ±5V, gain 1dB condition).

The baseline compensation circuit BL1 makes the noise baseline of the front-end components have extremely small fluctuations under full-temperature working conditions.

The operational amplifier OA1 here has a wide Gain Bandwidth Product (Gain Bandwidth Product) and a high Slew Rate (Slew Rate). The former affects the peak-to-peak value of the video output signal "Video Out" of the front-end components, usually not less than 20MHz. The latter affects the rising and falling edges of the "Video Out" pulse, usually not less than 750V/us.

In this embodiment, the fine-step numerically controlled attenuator AT4 adopts a GaAs MMIC numerically controlled attenuator, the insertion loss is not greater than 3dB, the step is 0.25dB, a total of two bits, the attenuation accuracy is ±0.2dB, and the TTL voltage control is adopted, and the switching time is not more than 20ns; the fine-step numerically controlled attenuator AT4 fine-tunes the gain of each intermediate frequency IF channel to improve the amplitude consistency between the intermediate frequency IF channels, and the number of bits does not exceed 4 bits.

In this embodiment, the amplifier AM2 adopts a GaAs MMIC low-noise amplifier, the gain is not less than 20dB, and the noise figure is less than 2dB; in order to meet the linear dynamic range of the front-end components, a higher output P-1 is required, and the output P-1 is 1dB The power at the compression point is not less than 15dBm.

(3) As shown in Figure 3, the self-inspection one-to-four power splitter network is formed by connecting the four output terminals of the one-point to four-power splitter SPW1 in series with a fixed attenuator SAT1 and an amplifier SAM1, and the one-to-four power splitter SPW1 The input terminal of the amplifier SAM1 is connected to the self-test signal, and the output terminal of the amplifier SAM1 is connected to the coupling port of the coupler CP1, so as to realize the self-test function.

The one-to-four power splitter SPW1 here uses GaAs MMIC 0° four-way power splitter chip, the frequency covers 30-40GHz, the in-band insertion loss is less than 1.5dB, the working bandwidth includes radio frequency frequency, and the isolation between the four channels is more than 18dB .

The fixed attenuator SAT1 here uses a GaAs MMIC fixed attenuator, which is composed of thin film resistors. It has extremely flat attenuation, small input and output return loss, and an attenuation of 6dB within the entire operating bandwidth.

The amplifier SAM1 here uses a GaAs MMIC low-noise amplifier, the frequency covers 30-40GHz, the gain is about 10dB, and it has a high reverse isolation (above 35dB), which is mainly used to improve the isolation between channels.

Improve the isolation between the four RF circuits by fixing the attenuation value of the attenuator SAT1 and the reverse isolation of the amplifier SAM1. Combined with the coupling degree of the coupler CP1, the isolation between the four RF circuits can reach more than 65dB (and the front end component’s linear dynamic range).

Through the one-to-four power splitter SPW1, the four-way fixed attenuator SAT1, and the amplifier SAM1, the power of the self-test signal is divided and amplified, and then connected to the coupling port of the four-way RF circuit coupler CP1 to realize the independent self-test function of each component. .

(4) As shown in Figure 4, the local oscillator's one-point-four-power-dividing network includes a phase-locked source (PLS) LS1, a band-pass filter LBP1, a power divider LPW1, and four output terminals of the power divider LPW1 in series. Connect one channel of frequency multiplier LMA1 and band-pass filter LBP2 respectively; the input terminal of phase-locked source LS1 is connected to the reference signal 100MHz, the power is 3dBm, and the output terminal of band-pass filter LBP2 is connected to the local oscillator port of mixer MX1, providing The local oscillator signal required for frequency mixing, the frequency of the local oscillator signal is 24GHz;

The phase-locked source LS1 here is composed of a voltage-controlled oscillator (VCO), a frequency divider chip and a voltage regulator chip, combined with a multi-layer printed board wiring process. It is small in size, simple in circuit and easy to integrate. The output frequency is 6GHz and the power About 5dBm, the phase noise is about -110dBc/Hz@1kHz.

The bandpass filter LBP1 here adopts a parallel coupled line structure, the intermediate frequency is 6GHz, and the sideband suppression reaches more than 20dB at 1GHz. The plate is made of ceramic AL2O3. Integrated with external microstrip signal transmission lines.

The power splitter LPW1 here adopts the microstrip Wilkinson cascade structure, the frequency is 6-18GHz, and the in-band insertion loss is not more than 9dB. The plate is made of ceramic AL2O3. The way is integrated with the external microstrip signal transmission line.

The frequency multiplier LMA1 here adopts a GaAs MMIC active quadrupler, which integrates a quadrupler and an output amplifier inside, suppresses the fundamental wave to more than 30dBc, and outputs more than 18dBm.

The bandpass filter LBP2 here adopts a parallel coupled line structure, the intermediate frequency is 24GHz, the in-band insertion loss is not greater than 2dB, and the suppression at 6GHz, 12GHz, 18GHz and 30-40GHz reaches more than 60dB. It is small in size and can be integrated with external microstrip signal transmission lines by bonding and gold wire bonding.

In this embodiment, the phase-locked source LS1 adopts a classic phase-locked loop (PLL) circuit, which is composed of a voltage-controlled oscillator (VCO), a frequency divider chip and a voltage regulator chip, combined with a multi-layer printed board wiring process. It has the advantages of small size, simple circuit and low phase noise.

In this embodiment, the center frequency of the bandpass filter LBP1 is the output frequency of the phase-locked source LS1, the insertion loss is within 3dB, and the half harmonic and the second harmonic of the output frequency are suppressed outside the band, and the suppression degree is within More than 50dB.

In this embodiment, the insertion loss at the output frequency of the power splitter LPW1, the one-to-four power splitter, and the phase-locked source LS1 is not greater than 4dB, and the isolation of the four-way power splitter is above 15dB.

In this embodiment, the frequency multiplier LMA1 is an active quadruple frequency multiplier, the input power is about 0 dBm, the output power is above 15 dBm, and the fundamental wave is suppressed above 25 dB.

In this embodiment, the center frequency of the bandpass filter LBP2 is the frequency of the local oscillator signal, the insertion loss is within 3 dB, and the output fundamental wave and the third harmonic of the LMA1 are out-of-band suppressed, and the suppression degree is above 55 dB.

In this embodiment, the one-to-four power division network of the local oscillator can effectively reduce the channel isolation problem caused by the leakage of the local oscillator through the combination of the four-way frequency multiplier LMA1 and the band-pass filter LBP2.

It can be seen that the local oscillator signal frequency can be determined according to the influence of clutter on the SDLVA video output signal, and then the internal parameters of the local oscillator one-to-four power distribution network can be determined; the noise figure of the entire link can be determined according to the SDLVA detection range And the gain range, and then confirm the internal parameters of the radio frequency circuit and the intermediate frequency circuit, the noise figure as low as possible and the instantaneous linear dynamic range as high as possible; through the switch and digitally controlled attenuator in the radio frequency circuit, the linear dynamics of the components can be expanded ;Through the temperature-compensated attenuator in the intermediate frequency circuit, the performance of the component under full temperature conditions can be optimized; through the fine-step digitally controlled attenuator in the intermediate frequency circuit, the consistency between channels can be improved; through the baseline compensation circuit in the intermediate frequency circuit , the noise baseline of the components has very small fluctuations under full temperature conditions; through the self-test one-point four-power distribution network, the components have a self-test function.

The multi-channel Ka-band front-end component provided by this embodiment has complex functions and high integration, and requires a reasonable facet design. The above-mentioned radio frequency circuits (four circuits in total), intermediate frequency circuits (four circuits in total) and some logic signals are placed on the front. and the wiring of the power supply. On the opposite side, the above-mentioned self-test one-point four-power distribution network, local oscillator one-point four-power distribution network, power management circuit and logic control circuit are placed. The back of all GaAs MMIC chips must be grounded, sintered with 80/20 gold tin, the sintering temperature should not exceed 300°C, and the sintering time should be as short as possible, not exceeding 30 seconds.

The assembly diagram is shown in Figure 5, and the entire cavity is divided into A side and B side. The four-way RF circuit and the four-way intermediate frequency circuit are concentrated on the A side of the component, and the mixed assembly process of micro-assembly and electric assembly is adopted, that is, the micro-assembly circuit is installed on the electric assembly circuit, and the temperature gradient needs to be reasonably designed during assembly, so that it can be used later. Debugging and maintainability; self-test one-point four-power distribution network, local oscillator one-point four-power distribution network, power management circuit and logic control circuit are concentrated on the B side of the module. The A side and the B side are connected through the DC transition and the RF vertical transition respectively. This assembly method reduces the circuit area and improves the integration of components.

Specifically, the A side adopts a mixed assembly process of micro-assembly and denso, that is, the micro-assembled circuit (soft substrate) is installed on the top of the denso circuit (printed board). Evenly apply an appropriate amount of alpha solder paste LR721H3 (62Sn36Pb2Ag) on the bottom of the printed board, with a small amount of flux, and weld it on the box body through a 220°C heating table; then install the partition wall on the surface of the printed board with screws and apply it on the surface with H20E conductive adhesive At the seam; finally, apply H20E conductive adhesive on the bottom surface of the soft substrate, bond it to the surface of the printed board, and cure it at 170°C for 30 minutes to complete the micro-assembly and electrical assembly. It is debuggable and maintainable in the later stage.

The performance indicators that can be achieved are as follows: input RF frequency covers 30~40GHz, input signal power: -65~+15dBm, Video Out (video signal) output instantaneous linear dynamic ≥ 50dB, IF (intermediate frequency signal) output instantaneous linear dynamic ≥ 40dB, Self-test signal frequency is 36GHz, IF signal output frequency is 6-16GHz, full temperature gain is 38±3dB, output signal spurious ≤ -25dBc, phase noise ≤ -80dBc/Hz@1kHz; Video Out (video signal) noise baseline is at full temperature 0～150mV, peak-to-peak value≤200mV, logarithmic slope 60±2.5mV/dB, logarithmic linearity≤±2dB, rising edge≤25ns, falling edge≤100ns, when injecting -65dBm signal, signal-to-noise ratio≥300mV; component The amplitude consistency between each channel is ≤±2dB, and the isolation is ≥65dBc.

The multi-channel Ka-band front-end component of the present invention adopts the millimeter-wave broadband mixing technology to mix the millimeter-wave signal to the low-frequency band, and then adopts the continuous logarithmic detection amplification (SDLVA) technology. Compared with the traditional millimeter-wave detection scheme, it has more advantages. Wide dynamic range, compared with the traditional DLVA scheme, it has a smaller volume; according to the influence of spurs on the SDLVA video output signal, the mixing scheme is determined, and the link gain is allocated reasonably, which has extremely high sensitivity while taking into account the relatively high Large instantaneous linear dynamic range, and the linear dynamic can be expanded; using SDLVA technology, the noise baseline is more stable than the traditional DLVA technology, additional temperature compensation attenuator and baseline compensation unit are added to reduce the impact of temperature on component performance, under full temperature conditions All have high stability; the internal assembly of the components adopts a mixed assembly process of micro-assembly and denso, which reduces the space occupied by more than 50%. All technical indicators of this module have reached the domestic leading level, and the integration degree is extremely high, but the requirements for assembly are low, and it is suitable for the millimeter wave direction finding system.

The above-mentioned embodiments only express the implementation manner of the present invention, and the description thereof is relatively specific and detailed, but should not be construed as limiting the patent scope of the present invention. It should be pointed out that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the appended claims.

Claims (2)

1. The utility model provides a multichannel Ka wave band front end subassembly, its characterized in that, front end subassembly operating frequency is 30 ~ 40GHz, divides the network and local oscillator one divides four merit to divide the network including four ways radio frequency circuit, four ways intermediate frequency circuit, self-checking one divide four merit, wherein:

the four radio frequency circuits consist of four identical radio frequency circuits, and each radio frequency circuit is formed by cascading a coupler, a first single-pole double-throw switch, a first amplifier, a fixed attenuator, a second single-pole double-throw switch, a radio frequency band-pass filter, a numerical control attenuator and a frequency mixer; the four intermediate frequency circuits consist of four identical intermediate frequency circuits, each intermediate frequency circuit comprises an intermediate frequency band-pass filter, a temperature compensation attenuator and a first power divider which are sequentially connected in series, one output of the first power divider is sequentially connected with a continuous logarithmic detection amplifier and a base line compensation circuit, and the other output of the first power divider is sequentially connected with a fine step numerical control attenuator and a second amplifier; the radio frequency circuit and the intermediate frequency circuit are connected in series in a one-to-one correspondence manner;

the coupler adopts a microstrip parallel coupling structure, the radio frequency band-pass filter adopts a three-line microstrip structure, the mixer adopts a passive double-balance MMIC mixer, and the intermediate frequency band-pass filter adopts a microstrip interdigital structure; the fine stepping numerical control attenuator adopts a GaAs MMIC numerical control attenuator, the insertion loss is not more than 3dB, the stepping is 0.25dB, the total number of the two positions is two, the attenuation precision is +/-0.2 dB, the TTL voltage is adopted for control, and the switching time is not more than 20ns;

the self-checking one-to-four power distribution network is respectively connected to the coupling ends of the couplers in the four-path radio frequency circuit, so that the self-checking function of the component is realized;

the local oscillator one-to-four power distribution network is respectively accessed to local oscillator ends of frequency mixers in the four-path radio frequency circuit to provide local oscillator signals required by component frequency mixing;

the first single-pole double-throw switch, the second single-pole double-throw switch, the first amplifier and the fixed attenuator form a linear dynamic expansion circuit; when a small signal smaller than a set threshold value enters a channel, the small signal is output after passing through the first single-pole double-throw switch, the first amplifier and the second single-pole double-throw switch by controlling the first single-pole double-throw switch and the second single-pole double-throw switch; when a large signal larger than a set threshold value enters a channel, the large signal is output after passing through the first single-pole double-throw switch, the fixed attenuator and the second single-pole double-throw switch by controlling the first single-pole double-throw switch and the second single-pole double-throw switch, so that the assembly always works in a linear working state;

the temperature compensation attenuator is formed by combining an electrically-controlled attenuator externally connected with a first temperature sensor, a singlechip and a digital-to-analog converter, wherein the first temperature sensor is used for acquiring ambient temperature and converting the ambient temperature into a digital signal, the digital signal is processed by the singlechip and then converted into an analog signal by the digital-to-analog converter, and the analog signal drives the electrically-controlled attenuator to change attenuation so as to achieve the purpose of temperature compensation;

the baseline compensation circuit comprises a second temperature sensor, a voltage bias circuit and an operational amplifier, wherein the second temperature sensor converts the ambient temperature into an analog signal and outputs the analog signal; the initial voltage value of the voltage bias circuit is selected as the noise level of the continuous logarithmic detection amplifier; the operational amplifier adopts a low-noise and high-speed current feedback type amplifier;

the self-checking one-to-four power distribution network is formed by respectively connecting four output ends of a one-to-four power divider in series with a fixed attenuator and a third amplifier, wherein the input end, namely the common end, of the one-to-four power divider is connected with a self-checking signal, and the output end of the third amplifier is connected with a coupling port of a coupler;

the local oscillator one-to-four power distribution network comprises a phase-locked source, a band-pass filter and a second power divider which are sequentially connected in series, wherein four output ends of the second power divider are respectively connected with a frequency multiplier and a band-pass filter; the input end of the phase-locked source is accessed with a reference signal of 100MHz and the power of 3dBm, and the output end of the band-pass filter is connected with a local oscillator port of the frequency mixer to provide a local oscillator signal required by frequency mixing;

the numerical control attenuator adopts a 2-digit numerical control attenuator integrally driven by GaAs MMIC, the frequency range covers 30-40GHz, the insertion loss is less than or equal to 4dB, the step is 10dB, the TTL logic control is adopted, and the switching speed of a switch is less than 20ns; when the small signal smaller than the set threshold enters the channel, the numerical control attenuator does not attenuate; when a large signal larger than a set threshold value enters a channel, if a subsequent device works in a nonlinear state, the numerical control attenuator attenuates according to 10dB, 20dB, 30dB and 40dB in sequence, so that the subsequent device always works in a linear working state, and the linear dynamic range expansion is realized.

2. The multi-channel Ka-band front-end module of claim 1, wherein the four RF circuits and four IF circuits are integrated on a first side of the module by a micro-assembly and electrical-device hybrid assembly process, i.e., the micro-assembly circuit is mounted on the electrical-device circuit; the self-checking one-to-four power distribution network and the local oscillator one-to-four power distribution network are centralized on the second surface of the component, and the first surface and the second surface are communicated through direct current transition and radio frequency vertical transition respectively.

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