WO2013008267A1

WO2013008267A1 - High-pass filters for high-speed data transmission systems

Info

Publication number: WO2013008267A1
Application number: PCT/JP2011/003939
Authority: WO
Inventors: Taras Kushta
Original assignee: Nec Corporation
Priority date: 2011-07-08
Filing date: 2011-07-08
Publication date: 2013-01-17

Abstract

A high-pass filter of the present invention is arranged in a multilayer substrate. A microstrip line and a signal via pad are arranged in a top conductive layer of the multilayer substrate and connected via a resistor. A signal via conductor is connected to the signal via pad by one end and penetrates through the multilayer substrate. A conductor plane is arranged in a bottom conductive layer of the multilayer substrate and connected to the other end of the signal via conductor. A substrate dielectric is arranged between the top and the bottom conductive layers and isolates a conductor plate from other conductors. The conductor plate is arranged in an intermediate conductive layer disposed between the top and bottom conductive layers, connected to the signal via conductor and acts with the substrate dielectric as an artificial medium having an effective relative permittivity higher than the relative permittivity of the substrate dielectric.

Description

HIGH-PASS FILTERS FOR HIGH-SPEED DATA TRANSMISSION SYSTEMS

This invention is related to high-pass filters for equalizing circuits used to reduce the Inter-Symbol Interference (ISI) in high-speed channels.

Modern and next-generation networking and computing systems need compact and cost-effective devices. Multilayer substrates serve as main interconnect technologies in the systems including a chip, a package and a printed circuit board (PCB). However, dispersion losses in a substrate and crosstalk effects become critical issues in a design of high-speed interconnections, especially in the gigahertz frequency range. These issues originate the ISI which limits the speed of data transmission through the interconnection area.

Passive equalization due to its low-energy consumption is one of the most promising techniques to overcome the ISI problem. Passive equalization can be realized by using a high-pass filter which can be disposed on-chip or off-chip area. The on-chip high-pass filter needs large area and, as a result, a high manufacturing cost. That is why, off-chip equalization structures are necessary to reduce the cost of the systems. In this case, package and PCB areas can be used.

In Japanese Laid Open Application JP2009-55284, passive equalizer circuits in which both distributed and lumped elements are applied are presented. However, large dimensions can be a problem in a case of application of such structures.

United States Laid Open Application US2008/0212283 shows electrical components, including filters, which are integrated with heat sinks.

In a non-patent paper (A Compact and Wide-Band Passive Equalizer Design Using a Stub with Defected Ground Structure for High Speed Data Transmission, IEEE Microwave and Wireless Component Letters, Vol. 20, No. 5, May 2010, pp. 256-258), a high-pass filter for equalization purposes has been described. This high-pass filter includes both discrete and distributed elements disposed in a PCB. However, large dimensions and radiation losses are those problems which can be arisen in the case of application of such high-pass filter in the systems.

United States Laid Open Application US2009/0206962. Japanese Laid Open Application JP2009-55284 United States Laid Open Application US2008/0212283 A Compact and Wide-Band Passive Equalizer Design Using a Stub with Defected Ground Structure for High Speed Data Transmission, IEEE Microwave and Wireless Component Letters, Vol. 20, No. 5, May 2010, pp. 256-258.

It is an object of the present invention to provide compact and low radiation loss high-pass filters, based on multilayer substrate technologies such as PCBs and packages, for a passive equalization in high speed data transmission systems.

In an aspect of this invention, high-pass filters are provided by a three-dimensional design, using both signal via and transmission line structures, and a specific artificial medium having a high effective permittivity. This artificial medium is formed by conductive plates connected to signal vias. These conductive plates have strong capacitive coupling between each other if they are disposed at the same conductor layer. Also, the conductive plates have enhanced capacitive coupling to ground or power plane arranged at the same conductor layer. A resistor connected to the transmission line and the signal via provides flatness of high-pass filter characteristics and as a result a wide bandwidth operation.

Fig. 1A is a vertical cross-sectional view illustrating a high-pass filter in an exemplary embodiment of the present invention. Fig. 1B is a top view of the high-pass filter shown in Fig. 1A. Fig. 1C is a horizontal cross-sectional view of the high-pass filter shown in Fig. 1A at the 1L2 and 1L3 layers. Fig. 1D is a bottom view of the high-pass filter shown in Fig. 1A. Fig. 1E is a drawing showing a simplified physical model of invented high-pass filter shown in Fig. 1A. Fig. 2A is a vertical cross-sectional view illustrating a high-pass filter in another exemplary embodiment of the present invention. Fig. 2B is a top view of the high-pass filter shown in Fig. 2A. Fig. 2C is a horizontal cross-sectional view of the high-pass filter shown in Fig. 2A at the 2L2, 2L3, 2L4, and 2L5 layers. Fig. 2D is a bottom view of the high-pass filter shown in Fig. 2A. Fig. 3A is a vertical cross-sectional view illustrating a high-pass filter in another exemplary embodiment of the present invention. Fig. 3B is a top view of the high-pass filter shown in Fig. 3A. Fig. 3C is a horizontal cross-sectional view of the high-pass filter shown in Fig. 3A at the 3L2, 3L3, 3L4, 3L5, 3L6, and 3L7 layers. Fig. 3D is a bottom view of the high-pass filter shown in Fig. 3A. Fig. 4 is a graph showing a simulated electrical performance of invented high-pass filter shown in Fig. 1. Fig. 5 is a perspective view showing a device of a relating art (IEEE Microwave and Wireless Component Letters (Vol.20, No.5, May 2010, pp.256-258).

Hereinafter, several types of high-pass filters based on multilayer substrates according to the present invention will be described in details with reference to attached drawings. But, it would be well understood that this description should not be viewed as narrowing the appended claims.

In Figs. 1A to 1E, an exemplary embodiment of a high-pass filter in a multilayer substrate is shown. This multilayer substrate is, as shown in Fig. 1A, a four-conductor-layer substrate including a top conductive layer or a first conductive layer 1L1, a second conductive layer or a first intermediate conductive layer 1L2, a third conductive layer or a second intermediate conductive layer 1L3 and a bottom conductive layer or a fourth conductive layer 1L4. The four conductive layers 1L1, 1L2, 1L3 and 1L4 are stacked from top to bottom in this order and isolated from each other by a dielectric 111. It should be noted that this four-conductor-layer substrate is only an example of multilayer substrates and a number of conductor layers, filling material and other substrate parameters can be different.

Fig. 1A is a vertical cross-sectional view illustrating a high-pass filter in an exemplary embodiment of the present invention. The high-pass filter of this exemplary embodiment includes four conductor planes 107, a pair of signal via conductors 101, a pair of signal via pads 104, clearance holes 103, a pair of microstrip lines 106, four conductive plates 108, a pair of resistors 105 and a dielectric 111.

The first conductor plane 107, the pair of microstrip lines 106, the pair of signal via pads 104 and the clearance holes 103 are arranged in the first conductive layer 1L1. The second conductive plane 107 and a first conductive plate pair 108 are arranged in the second conductive layer 1L2. The third conductive plane 107 and a second conductive plate pair 108 are arranged in the third conductive layer 1L3. The fourth conductive plane 107 is arranged in the fourth conductive layer 1L4.

The pair of the signal via conductors 101 penetrates the multilayer substrate. The pair of the signal via conductors 101 is connected by one end to the pair of the signal via pads 104, respectively. The pair of the signal via conductors 101 is connected by another end to the fourth conductive plane 107.

Each of four conductive plates 108 is connected to one of the pair of signal via conductors 101.

Each of the pair of resistors 105 is disposed on the first conductive layer 1L1. The first microstrip line 106 is connected to one end of the first resistor 105. The other end of the first resistor 105 is connected to the first signal via pad 104. The second microstrip line 106 is connected to one end of the second resistor 105. The other end of the second resistor 105 is connected to the second signal via pad 104.

Fig. 1B is a top view of the high-pass filter shown in Fig. 1A. The first clearance hole 103 isolates the first microstrip line 106 and the first signal via pad 104 from the first conductive plane 107. The second clearance hole 103 isolates the second microstrip line 106 and the second signal via pad 104 from the first conductive plane 107.

Fig. 1C is a horizontal cross-sectional view of the high-pass filter shown in Fig. 1A at the conductive layers 1L2 and 1L3. Each of the first and the second conductive plates 108 has a concave section and a convex section under the microstrip lines 106. The concave section of the first conductive plate 108 is in correspondence with the convex section of the second conductive plate 108. The convex section of the first conductive plate 108 is in correspondence with the concave section of the second conductive plate 108. As Fig. 1C shows, the concave section and the convex section in this embodiment have a rectangular shape, but this characteristic is not a limitation over the present invention. An isolating slit 109 is arranged between the concave section and the convex section and isolates the first and the second conductive plates 108. The concave section, the convex section in correspondence with the concave section and the dielectric filled in the isolating slit 109 disposed between the concave section and the convex section act as a coupling section.

Fig. 1D is a bottom view of the high-pass filter shown in Fig. 1A. As Fig. 1D shows, the signal via conductors 101 in the present embodiment penetrate the bottom conductor plane 107.

Fig. 1E is a drawing showing a simplified physical model of invented high-pass filter shown in Fig. 1A. An artificial medium 113 is formed under the microstrip lines 106. The artificial medium 113 is, in fact, a set of the conductive plates 108 and the substrate dielectric around the conductive plates 108. In another words, the conductive plates 108 and the substrate dielectric around the conductive plates 108 act as an artificial medium 113.

This artificial medium 113 can be characterized by the effective relative permittivity which is dependent on dimensions of conductive plates 108, isolating slits 109 and coupling sections 110. In Fig. 1E, a physical model explaining this mechanism is presented. Magnitude of this effective permittivity can be much higher than the relative permittivity of the substrate dielectric 111. That is:

As a result, a resonant element, which is a basis of the high-pass filter proposed, can be miniaturized. In present embodiment, this resonant element is the signal via 101, including the pad 104.

Important role in the high-pass filter described plays the resistor 105 which is used to control filter characteristics at zero hertz or at very low frequencies. Moreover, this resistor serves to control the Q-factor (quality factor) of the high-pass filter and, as consequence, the bandwidth of the high-pass filter.

It should be noted that the resistor 105 can be provided as a discrete component, as for an example, a surface mounted resistor or a chip resistor. Also such resistor can be fabricated by means a film technology, including carbon nanotube one.

Ends 112 of the microstrip lines 106 act as input and output terminals for the presented high-pass filter.

In Figs. 2A to 2D, another exemplary embodiment of the high-pass filter in a multilayer substrate is shown. This multilayer substrate is, as shown in Fig. 2A, a six-conductor-layer substrate including a top conductor layer or a first conductor layer 2L1, a first intermediate conductive layer or a second conductive layer 2L2, a second intermediate conductive layer or a third conductive layer 2L3, a third intermediate conductive layer of a fourth conductive layer 2L4, a fourth intermediate conductive layer or a fifth conductive layer 2L5, and a bottom conductive layer or a sixth conductive layer 2L6. The conductive layers 2L1 to 2L6 are stacked from top to bottom in this order and isolated each other by a dielectric 211. It should be noted that this six-conductor-layer substrate is only an example of multilayer substrates and a number of conductor layers, filling material and other substrate parameters can be different.

Fig. 2A is a vertical cross-sectional view illustrating a high-pass filter in another exemplary embodiment of the present invention. The high-pass filter of this exemplary embodiment includes six conductor planes 207, a signal via conductor 201, a signal via pad 204, a clearance hole 203, a microstrip line 206, a group of conductive plates 208, a resistor 205, a group of ground vias 202 and a dielectric 211.

The first conductor plane 207, the microstrip line 206, the signal via pad 204 and the clearance hole 203 are arranged in the first conductive layer 2L1. The second conductive plane 207 and a first conductive plate 208 are arranged in the second conductive layer 2L2. The third conductive plane 207 and a second conductive plate 208 are arranged in the third conductive layer 2L3. The fourth conductive plane 207 and a third conductive plate 208 are arranged in the fourth conductive layer 2L4. The fifth conductive plane 207 and a fourth conductive plate 208 are arranged in the fifth conductive layer 2L5. The sixth conductive plane 207 is arranged in the sixth conductive layer 2L6.

The signal via conductor 201 penetrates the multilayer substrate. The signal via conductor 201 is connected by one end to the signal via pad 204. The signal via conductor 201 is connected by another end to the sixth conductive plane 207.

Each of four conductive plates 208 is connected to the signal via conductor 201.

The resistor 205 is disposed on the first conductive layer 2L1. The microstrip line 206 is connected to one end of the resistor 205. The other end of the resistor 205 is connected to the signal via pad 204.

Fig. 2B is a top view of the high-pass filter shown in Fig. 2A. The clearance hole 203 isolates the microstrip line 206 and the signal via pad 204 from the first conductive plane 207. The group of ground vias 202 surrounds the signal via conductor 201.

Fig. 2C is a horizontal cross-sectional view of the high-pass filter shown in Fig. 2A at the conductive layers 2L2, 2L3, 2L4 and 2L5. Each of the four conductive plates 208 respectively arranged in the four intermediate conductive layers 2L2, 2L3, 2L4 and 2L5 has a convex section under the microstrip line 206. Each of the four conductive planes 207 respectively arranged in the four intermediate conductive layers 2L2, 2L3, 2L4 and 2L5 has a concave section under the microstrip line 206. In each of the four intermediate conductive layers 2L2, 2L3, 2L4 and 2L5, the convex section in the conductive plate 208 is in correspondence with the concave section in the conductive plane 207. As Fig. 2C shows, the convex sections and the concave sections in this embodiment have a triangular shape, but this characteristic is not a limitation over the present invention. An isolating slit 209 is arranged between the convex section and the concave section both arranged in a same intermediate conductive layer. The isolating slit 209 isolates the convex section and the concave section both arranged in a same intermediate conductive layer. The convex section, the concave section in correspondence with the convex section and the dielectric filled in the isolating slit 209 disposed between the convex section and the concave section act as coupling sections 213.

Fig. 2D is a bottom view of the high-pass filter shown in Fig. 2A. As Fig. 2D shows, the signal via conductor 201 in the present embodiment penetrates the bottom conductor plane 207.

The conductive plates 208 arranged in the intermediate conductive layers and connected to the signal via conductor 201 and the dielectric 211 around the conductive plates 208 act as an artificial medium which provides compactness of the resonant element based on the signal via conductor 201. The coupling sections 213 serve to increase the effective permittivity of the artificial medium.

Ends 212 of the microstrip line 206 act as input and output terminals the high-pass filter proposed.

In Figs. 3A to 3D, further another exemplary embodiment of a high-pass filter in a multilayer substrate is shown. This multilayer substrate is, as shown in Fig. 3A, an eight-conductor layer substrate including a top conductive layer or a first conductive layer 3L1, a second conductive layer or a first intermediate conductive layer 3L2, a third conductive layer or a second intermediate conductive layer 3L3, a fourth conductive layer or a third intermediate conductive layer 3L4, a fifth conductive layer or a fourth intermediate conductive layer 3L5, a sixth conductive layer or a fifth intermediate conductive layer 3L6, a seventh conductive layer or a sixth intermediate conductive layer 3L7 and an eighth conductive layer or a bottom conductive layer 3L8. The eight conductive layers 3L1, 3L2, 3L3, 3L4, 3L5, 3L6, 3L7 and 3L8 are stacked from top to bottom in this order and isolated from each other by a dielectric 311. It should be noted that this eight-conductor-layer substrate is only an example of multilayer substrates and a number of conductor layers, filling material and other substrate parameters can be different.

Fig. 3A is a vertical cross-sectional view illustrating a high-pass filter in further another exemplary embodiment of the present invention. The high-pass filter of this exemplary embodiment includes eight conductor planes 307, a pair of signal via conductor 301, a pair of signal via pads 304, a pair of clearance holes 303, a pair of microstrip lines 306, a group of conductive plates 308, a pair of resistors 305 and a dielectric 311.

The first conductor plane 307, the pair of microstrip lines 306, the pair of signal via pads 304 and the pair of clearance holes 303 are arranged in the first conductive layer 3L1. The second conductive plane 307 and a first conductive plate pair 308 are arranged in the second conductive layer 3L2. The third conductive plane 307 and a second conductive plate pair 308 are arranged in the third conductive layer 3L3. The fourth conductive plane 307 and a third conductive plate pair 308 are arranged in the fourth conductive layer 3L4. The fifth conductive plane 307 and a fourth conductive plate pair 308 are arranged in the fifth conductive layer 3L5. The sixth conductive plane 307 and a fifth conductive plate pair 308 are arranged in the sixth conductive layer 3L6. The seventh conductive plane 307 and a sixth conductive plate pair 308 are arranged in the seventh conductive layer 3L7. The eighth conductive plane 307 is arranged in the eighth conductive layer 3L8.

Each of the pair of the signal via conductors 301 penetrates the multilayer substrate. The pair of the signal via conductors 301 is connected by one end to the pair of the signal via pads 304, respectively. The pair of the signal via conductors 301 is connected by another end to the eighth conductive plane 307.

Each of the conductive plates 308 is connected to one of the pair of signal via conductors 301.

Each of the pair of resistors 305 is disposed on the first conductive layer 3L1. The first microstrip line 306 is connected to one end of the first resistor 305. The other end of the first resistor 305 is connected to the first signal via pad 304. The second microstrip line 306 is connected to one end of the second resistor 305. The other end of the second resistor 305 is connected to the second signal via pad 304.

Fig. 3B is a top view of the high-pass filter shown in Fig. 3A. The first clearance hole 303 isolates the first microstrip line 306 and the first signal via pad 304 from the first conductive plane 307. The second clearance hole 303 isolates the second microstrip line 306 and the second signal via pad 304 from the first conductive plane 307. A first group of ground via conductors 302 surrounds the first signal via conductor 301. A second group of ground via conductors 302 surrounds the second signal via conductor 301.

Fig. 3C is a horizontal cross-sectional view of the high-pass filter shown in Fig. 3A at the intermediate conductive layers 3L2, 3L3, 3L4, 3L5, 3L6 and 3L7. Each of the conductive plates 308 has a concave section and a convex section under the microstrip lines 306. The concave section of the first conductive plate 308 is in correspondence with the convex section of the second conductive plate 308. The convex section of the first conductive plate 308 is in correspondence with the concave section of the second conductive plate 308. As Fig. 1C shows, the concave section and the convex section in this embodiment have a rectangular shape, but this characteristic is not a limitation over the present invention. An isolating slit 309 is arranged between the concave section and the convex section and isolates the first and the second conductive plates 308. The concave section under the microstrip lines 306, the convex section in correspondence with the concave section and the dielectric filled in the isolating slit 309 disposed between the concave section and the convex section act as a first coupling section 310.

Each of the conductive plates 308 has another convex section between the ground via conductors 302. Each of the conductive planes 307 has another concave section between the ground via conductors 302. The other convex section of the conductive plates 308 is in correspondence with the other concave section of the conductive planes 307. An isolating slit 309 is arranged between the other convex section and the other concave section and isolates the other convex section from the other concave section. The other convex section, the other concave section in correspondence with the other convex section and the isolating slit 309 isolating the other convex section from the other concave section act as another coupling section 313.

Fig. 3D is a bottom view of the high-pass filter shown in Fig. 3A. As Fig. 3D shows, the pair of signal via conductors 301 in the present embodiment penetrates the bottom conductor plane 307.

The conductive plates 308 arranged in the intermediate conductive layers and connected to the signal via conductors 301 and the dielectric 311 around the conductive plates 308 act as an artificial medium. The artificial medium is formed under the microstrip lines 306 by means of conductive plates 308 connected to the signal vias 301 and isolated from ground planes 307 by isolating slits 309. Also signal via conductive plates 308 disposed in the same layer (3L2, 3L3, 3L4, 3L5, 3L6, or 3L7) are coupled with each other through a coupling section 310. Moreover, these conductive plates 308 have coupling sections 313 with ground plates 307. Coupling sections 310 and 313 are applied to increase the effective permittivity of artificial medium and in such way to provide compactness of the high-pass filters.

Fig. 4 is a graph showing a simulated electrical performance of invented high-pass filter shown in Fig. 1. In Fig. 4, simulated data for the filter are presented by means of magnitudes of S-Parameters where |S₂₁| is for insertion loss and |S₁₁| is for return losses.

To show the electrical performance of a high-pass filter invented, a full-wave simulation for the exemplary embodiment shown in Figs.1A-1E was carried out by the Finite-Difference Time-Domain (FDTD) technique.

In the high-pass filter structure considered, four copper conductive layers were isolated by a dielectric having the relative permittivity 4.17 and loss tangent 0.023, corresponding FR-4 (Flame Retardant 4) material. Other dimensions of the filter structure were as following: the thickness of the four-conductor-layer substrate was 2.07mm; the thickness of copper conductor layers was 0.035mm; the diameter of the signal vias was 0.3mm; the pad diameter was 0.4mm; the distance between centers of signal vias was 1.8mm; the rectangular clearance area had the width of 1.6mm and the length of 2.6mm; the resistor was 20Ohms; conductive plates forming the artificial medium and connected to signal vias were separated from conductors planes by isolating slits of 0.1-mm width, including coupling sections.

(Related Art)
In Figs.5, a relating art, corresponding to the paper (A Compact and Wide-Band Passive Equalizer Design Using a Stub with Defected Ground Structure for High Speed Data Transmission, IEEE Microwave and Wireless Component Letters, Vol.20, No.5, May 2010, pp.256-258), is shown.

While the present invention has been described in relation to some exemplary embodiments, it is to be understood that these exemplary embodiments are for the purpose of description by example, and not of limitation. While it will be obvious to those skilled in the art upon reading the present specification that various changes and substitutions may be easily made by equal components and art, it is obvious that such changes and substitutions lie within the true scope and spirit of the presented invention as defined by the claims.

Claims

A high-pass filter arranged in a multilayer substrate, comprising:
a microstrip line arranged in a top conductive layer of said multilayer substrate;
a signal via conductor configured to penetrate through said multilayer substrate;
a signal via pad arranged in said top conductive layer and connected to one end of said signal via conductor;
a resistor of which two ends are connected to said microstrip line and said signal via pad respectively;
a conductor plane arranged in a bottom conductive layer of said multilayer substrate and connected to an other end of said signal via conductor;
a conductor plate arranged in an intermediate conductive layer of said multilayer substrate which is disposed between said top conductive layer and said bottom conductive layer, disposed under said microstrip line and connected to said signal via conductor; and
a substrate dielectric disposed between said top conductive layer and said bottom conductive layer and configured to isolate said conductor plate from other conductors,
wherein said conductor plate and a part of said substrate dielectric disposed around said conductor plate act as an artificial medium with an effective relative permittivity which is higher than a relative permittivity of said substrate dielectric, and
wherein ends of said microstrip line act as input and output terminals of said high-pass filter.
The high-pass filter according to claim 1, further comprising:
a top conductive plane arranged in said top conductive layer;
a clearance hole arranged in said top conductive layer and configured to isolate said signal via pad from said top conductive plane;
an intermediate conductive plane arranged in said intermediate conductive layer; and
an isolating slit arranged in said intermediate conductive layer, configured to isolate said conductive plate from said intermediate conductive plane and filled by said substrate dielectric.
The high-pass filter according to claim 2, further comprising:
a plurality of ground vias configured to penetrate through said multilayer substrate and surround said signal via conductor, and
wherein two ends of each of said plurality of ground vias are connected to said top conductive plane and said bottom conductive plane respectively.
The high-pass filter according to claim 3, further comprising:
a coupling section between said conductor plate and said conductive plane,
wherein said coupling section comprises:
a convex or concave section of said conductive plate;
a concave or convex section of said conductive plane in correspondence with said convex of concave section of said conductive plate; and
a section of said isolating slit disposed between said convex or concave section of said conductive plate and said concave or convex section of said conductive plane.
The high-pass filter according to claim 1, further comprising:
another microstrip line arranged in said top conductive layer;
another signal via conductor configured to penetrate through said multilayer substrate;
another signal via pad arranged in said top conductive layer and connected to one end of said another signal via conductor;
another resistor of which two ends are connected to said another microstrip line and said another signal via pad respectively; and
another conductor plate arranged in said intermediate conductive layer, disposed under said another microstrip line and connected to said another signal via conductor;
wherein said substrate dielectric is further configured to isolate said another conductor plate from other conductors,
wherein said another conductor plate and another part of said substrate dielectric disposed around said another conductor plate act as said artificial medium, and
wherein ends of said another microstrip line act as input and output terminals of said high-pass filter.
The high-pass filter according to claim 5, further comprising:
a top conductive plane arranged in said top conductive layer;
a clearance hole arranged in said top conductive layer and configured to isolate said signal via pad from said top conductive plane;
another clearance hole arranged in said top conductive layer and configured to isolate said another signal via pad from said top conductive plane;
an intermediate conductive plane arranged in said intermediate conductive layer; and
an isolating slit arranged in said intermediate conductive layer, configured to isolate said conductive plate and said another conductive plate from said intermediate conductive plane and filled by said substrate dielectric.
The high-pass filter according to claim 6, further comprising:
a coupling section between said conductor plate and said another conductor plate,
wherein said coupling section comprises:
a convex or concave section of said conductor plate;
a concave or convex section of said another conductor plate in correspondence with said convex or concave section of said conductive plate; and
a section of said isolating slit disposed between said convex or concave section of said conductive plate and said concave or convex section of said another conductive plate.
The high-pass filter according to claim 6 or 7, further comprising:
a plurality of ground vias configured to penetrate through said multilayer substrate and surround said signal via conductor; and
another plurality of ground vias configured to penetrate through said multilayer substrate and surround said another signal via conductor,
wherein two ends of each of said plurality of ground vias are connected to said top conductive plane and said bottom conductive plane respectively, and
wherein two ends of each of said another plurality of ground vias are connected to said top conductive plane and said bottom conductive plane respectively.
The high-pass filter according to claim 8, further comprising:
a coupling section between said conductor plate and said conductive plane,
wherein said coupling section comprises:
a convex or concave section of said conductive plate;
a concave or convex section of said conductive plane in correspondence with said convex of concave section of said conductive plate; and
a section of said isolating slit disposed between said convex or concave section of said conductive plate and said concave or convex section of said conductive plane.
The high-pass filter according to any of claims 1 to 9,
wherein said resistor is mounted on a surface of said top conductive layer.