JP2009004606A - Balun transformer and characteristic adjusting method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that although a balun transformer is preferably compact and short as mobile communication equipment becomes compact and short, unnecessary magnetic and capacitive coupling is apt to be generated between strip lines and between conductor patterns for coils and then signals output from a pair of balancing terminals have a large difference in magnitude and deteriorate in phase difference. <P>SOLUTION: An insulator layer and a conductor pattern are stacked. The stacked body of them includes a first coil and a second coil which are connected in series by the conductor pattern and one of which is connected to an imbalancing terminal, a third coil which is electromagnetically coupled to the first coil and connected between a first balancing terminal and a ground, a fourth coil which is electromagnetically coupled to the second coil and connected between a second balancing terminal and the ground, and a capacitor connected between the second balancing terminal and the ground. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an impedance converter for converting the impedance of a transmission line, a signal converter or a phase converter for converting a balanced transmission line signal and an unbalanced transmission line signal to each other in a mobile communication device or the like. The present invention relates to a balun transformer used in a ceramic device and its characteristic adjustment method.

As shown in FIG. 5, the conventional balun transformer includes an insulator layer 51A in which a ground electrode G1 is formed, an insulator layer 51B in which spiral strip lines 52 and 53 of λ / 4 are formed, a first An insulator layer 51C in which a λ / 2 strip line composed of a portion 54A and a second portion 54B is formed, an insulator layer 51D in which an extraction electrode 55 connected to the first portion 54A is formed, and a ground electrode G2 There is a so-called Marchand type in which the insulating layer 51E formed of is laminated, the stripline 52 and the first portion 54A are electromagnetically coupled, and the stripline 53 and the second portion 54B are electromagnetically coupled (for example, (See Patent Document 1).
In another conventional balun transformer, an insulator layer and a coil conductor pattern are laminated, and a coil L5 and a coil L6 are connected in series between the unbalanced terminal 61 and the dummy terminal 64, thereby making a pair of balancing elements. There is a lumped constant type in which a coil L7 and a coil L8 are connected in series between terminals 62 and 63, a coil L5 and a coil L7 are electromagnetically coupled, and a coil L6 and a coil L8 are electromagnetically coupled (for example, a patent) See reference 2.)

JP-A-7-76918 JP 2001-176726 A

  In recent years, mobile communication devices such as mobile phones have been further reduced in size and height. Accordingly, this type of balun transformer used in mobile communication devices is also desired to be reduced in size and height. In order to reduce the size and height of the conventional balun transformer, use a material with a high dielectric constant for the insulator layer, or reduce the spacing between the stripline and coil conductor pattern. However, unnecessary magnetic and capacitive coupling easily occurs between strip lines and coil conductor patterns, resulting in a difference in the magnitude of signals output from a pair of balancing terminals. There has been a problem that the phase difference of signals output from the pair of balancing terminals deteriorates. Therefore, the conventional balun transformer could not be sufficiently reduced in size and height.

  The present invention can reduce the difference in the magnitude of the signal output from the pair of balancing terminals and reduce the size of the signal output from the pair of balancing terminals. An object of the present invention is to provide a balun transformer capable of reducing the deterioration of the phase difference and a method for adjusting the characteristics thereof.

The balun transformer of the present invention includes an insulator layer and a conductor pattern laminated, a first coil and a second coil connected in series by the conductor pattern in these laminates, one of which is connected to an unbalanced terminal, Electromagnetically coupled to the first coil, third coil connected between the first balancing terminal and ground, and electromagnetically coupled to the second coil, between the second balancing terminal and ground A fourth coil connected and a capacitor connected between the second balancing terminal and the ground are provided.
According to the balun transformer characteristic adjusting method of the present invention, an insulator layer and a conductor pattern are laminated, a first coil connected in series by the conductor pattern in the laminate, and one of which is connected to an unbalanced terminal; A second coil, electromagnetically coupled to the first coil, and a third coil connected between the first balancing terminal and ground; and a second coil, electromagnetically coupled to the second coil; And a capacitor connected between the second balancing terminal and the ground, and a signal output from a pair of balancing terminals depending on the capacitance of the capacitor And the phase difference of signals output from a pair of balancing terminals are adjusted.

The balun transformer of the present invention includes an insulator layer and a conductor pattern laminated, a first coil and a second coil connected in series by the conductor pattern in these laminates, one of which is connected to an unbalanced terminal, Electromagnetically coupled to the first coil, third coil connected between the first balancing terminal and ground, and electromagnetically coupled to the second coil, between the second balancing terminal and ground Since the fourth coil connected and the capacitor connected between the second balancing terminal and the ground are provided, even if the shape is reduced in size and height, the signal output from the pair of balancing terminals And the deterioration of the phase difference of the signals output from the pair of balancing terminals can be reduced.
The balun transformer characteristic adjustment method of the present invention includes a first method in which an insulator layer and a conductor pattern are stacked, connected in series by the conductor pattern in the stack, and one is connected to an unbalanced terminal. A coil, a second coil, electromagnetically coupled to the first coil, a third coil connected between the first balancing terminal and ground, and an electromagnetically coupled to the second coil; A fourth coil connected between the balancing terminal and ground and a capacitor connected between the second balancing terminal and ground, and output from a pair of balancing terminals depending on the capacitance of the capacitor The output signal is output from the pair of balancing terminals even if the shape is reduced in size and height. The difference in signal magnitude can be reduced, and a pair of signals It is possible to reduce the deterioration of the phase difference signal outputted from 衡用 terminal.

  In the balun transformer of the present invention, an insulator layer, a coil conductor pattern, and a capacitor conductor pattern are laminated. The first and second coils, which are connected in series in the laminate by the coil conductor pattern and the capacitor conductor pattern between the insulator layers, one of which is connected to the unbalanced terminal, are electromagnetically connected to the first coil. A third coil connected between the first balancing terminal and the ground, and a fourth coil connected electromagnetically to the second coil and connected between the second balancing terminal and the ground. A balun transformer including a capacitor connected between the second balancing terminal and the ground is formed. Therefore, the balun transformer of the present invention has a difference in the magnitude of the signal output from the pair of balancing terminals and the pair of balancing balances depending on the capacitance of the capacitor connected between the second balancing terminal and the ground. The phase difference of the signal output from the terminal can be adjusted.

The balun transformer and its characteristic adjustment method of the present invention will be described below with reference to FIGS.
1 is a circuit diagram of an embodiment of the balun transformer of the present invention, FIG. 2 is an exploded perspective view showing an embodiment of the balun transformer of the present invention, and FIG. 3 is a perspective view showing an embodiment of the balun transformer of the present invention.
In FIG. 1, 11 is an unbalanced terminal, 12 is a first balancing terminal, and 13 is a second balancing terminal.
A coil L1 and a coil L2 connected in series are connected to the unbalance terminal 11. A coil L3 is connected between the first balancing terminal 12 and the ground. A coil L4 is connected between the second balancing terminal 13 and the ground. A capacitor C1 is connected between the second balancing terminal 13 side of the coil L4 and the ground.
Then, the coil L1 and the coil L3 are electromagnetically coupled, and the coil L2 and the coil L4 are electromagnetically coupled.
A signal input from the unbalance terminal 11 is transmitted from the coil L1 to the coil L3, and is transmitted from the coil L2 to the coil L4. The signals transmitted to the coils L3 and L4 are output from the balancing terminals 12 and 13. At this time, since the capacitor C1 is provided between the balancing terminal 13 and the ground, the self-resonance frequency of the coil L4 decreases, and the magnitude of the signal output from the balancing terminal 12 and the magnitude of the signal output from the balancing terminal 13 are reduced. The difference in height and the phase difference between the signal output from the balancing terminal 12 and the signal output from the balancing terminal 13 change. The capacitance of the capacitor C1 reduces the influence of unnecessary magnetic and capacitive coupling generated between the coil conductor patterns, so that the magnitude of the signal output from the balancing terminal 12 and the signal output from the balancing terminal 13 are reduced. Is set so that the phase difference between the signal output from the balancing terminal 12 and the signal output from the balancing terminal 13 is always 180 degrees.
In addition, signals input from the balancing terminals are transmitted from the coils L3 and L4 to the coils L1 and L2, respectively. The signals transmitted to the coils L1 and L2 are combined and output from the unbalanced terminal 11.

In the balun transformer having such a circuit configuration, as shown in FIG. 2, an insulating layer and a conductor pattern are laminated to form a circuit element in the laminated body.
The insulator layers 21A to 21M are formed using an insulating material such as a magnetic material, a non-magnetic material, and a dielectric material.
The insulator layer 21A has a surface on which no conductor pattern is formed.
A coil conductor pattern 22A and a coil conductor pattern 23A are formed on the surface of the insulator layer 21B. The coil conductor pattern 22A and the coil conductor pattern 23A are each formed with less than one turn, and one end of the coil conductor pattern 22A and one end of the coil conductor pattern 23A are connected to each other.
A coil conductor pattern 22B and a coil conductor pattern 23B are formed on the surface of the insulator layer 21C. The coil conductor pattern 22B and the coil conductor pattern 23B are formed so as to be symmetrical with each other for less than one turn. One end of the coil conductor pattern 22B is connected to the other end of the coil conductor pattern 22A through a through hole formed in the insulator layer 21C. One end of the coil conductor pattern 23B is connected to the other end of the coil conductor pattern 23A through a through hole formed in the insulator layer 21C.
A coil conductor pattern 22C and a coil conductor pattern 23C are formed on the surface of the insulating layer 21D. The coil conductor pattern 22C and the coil conductor pattern 23C are formed to be line-symmetric with each other. One end of the coil conductor pattern 22C is connected to the other end of the coil conductor pattern 22B through a through hole in the insulator layer 21D. One end of the coil conductor pattern 23C is connected to the other end of the coil conductor pattern 23B through a through hole in the insulator layer 21D.
A coil conductor pattern 22D and a coil conductor pattern 23D are formed on the surface of the insulator layer 21E. The coil conductor pattern 22D and the coil conductor pattern 23D are each formed for less than one turn. One end of the coil conductor pattern 22D is connected to the other end of the coil conductor pattern 22C through the through hole of the insulator layer 21E, and the other end is drawn to the side surface of the insulator layer 21E. One end of the coil conductor pattern 23D is connected to the other end of the coil conductor pattern 23C through a through-hole in the insulator layer 21E, and the other end is positioned near the side surface of the insulator layer 21E and floated in potential. Put into a state. In this manner, the coil conductor pattern 22A, the coil conductor pattern 22B, the coil conductor pattern 22C, and the coil conductor pattern 22D are spirally connected to form the coil L1, and the coil conductor pattern 23A and the coil conductor pattern are formed. 23B, the coil conductor pattern 23C and the coil conductor pattern 23D are spirally connected to form the coil L2. The coil L1 and the coil L2 are connected to each other by connecting the coil conductor pattern 22A and the coil conductor pattern 23A.
A coil conductor pattern 24A and a coil conductor pattern 25A are formed on the surface of the insulator layer 21F. The coil conductor pattern 24A and the coil conductor pattern 25A are each formed with less than one turn, and one end of the coil conductor pattern 24A and one end of the coil conductor pattern 25A are connected to each other. The common connection point between the coil conductor pattern 24A and the coil conductor pattern 25A is drawn to the side surface of the insulator layer 21F.
A coil conductor pattern 24B and a coil conductor pattern 25B are formed on the surface of the insulator layer 21G. The coil conductor pattern 24B and the coil conductor pattern 25B are formed so as to be symmetrical with each other for less than one turn. One end of the coil conductor pattern 24B is connected to the other end of the coil conductor pattern 24A through a through hole in the insulator layer 21G. One end of the coil conductor pattern 25B is connected to the other end of the coil conductor pattern 25A through the through hole of the insulator layer 21G. The coil conductor pattern 24C and the coil conductor are provided on the surface of the insulator layer 21H. Conductive pattern 25C is formed. The coil conductor pattern 24C and the coil conductor pattern 25C are formed so as to be line-symmetric with each other. One end of the coil conductor pattern 24C is connected to the other end of the coil conductor pattern 24B through a through hole in the insulator layer 21H. One end of the coil conductor pattern 25C is connected to the other end of the coil conductor pattern 25B through a through hole in the insulator layer 21H.
A coil conductor pattern 25D is formed on the surface of the insulator layer 21I. One end of the coil conductor pattern 25D is connected to the other end of the coil conductor pattern 25C through the through hole of the insulator layer 21I, and the other end is drawn to the side surface of the insulator layer 21I. In this way, the coil conductor pattern 25A, the coil conductor pattern 25B, the coil conductor pattern 25C, and the coil conductor pattern 25D are spirally connected to form the coil L4.
A coil conductor pattern 24D is formed on the surface of the insulator layer 21J. One end of the coil conductor pattern 24D is connected to the other end of the coil conductor pattern 24C through the through holes of the insulator layers 21J and 21I, and the other end is drawn to the side surface of the insulator layer 21J. In this way, the coil conductor pattern 24A, the coil conductor pattern 24B, the coil conductor pattern 24C, and the coil conductor pattern 24D are spirally connected to form the coil L3. The coil L3 and the coil L4 are connected to each other by connecting the coil conductor pattern 24A and the coil conductor pattern 25A, and the common connection end of the coil conductor pattern 24A and the coil conductor pattern 25A is the side surface of the insulator layer. Is pulled out and connected to earth.
A capacitor conductive pattern 26 is formed on the surface of the insulating layer 21K. Capacitor conductor pattern 26 is drawn out to the side surface of insulator layer 21K.
A capacitor conductive pattern 27 is formed on the surface of the insulating layer 21L. The capacitor conductor pattern 27 is formed at a position facing the capacitor conductor pattern 26, and the lead-out end is drawn to the side surface of the insulator layer 21L.
Terminal electrodes 31, 32, 33, and 34 are formed on the side surfaces of the laminated body that is laminated from the insulating layer 21 </ b> A to the insulating layer 21 </ b> L and covered with the protective insulating layer 21 </ b> M.
Then, the other end of the coil conductor pattern 22D is connected to the terminal electrode 31, whereby the coil L1 and the coil L2 connected in series are connected to the unbalanced terminal 11. Further, the other end of the coil conductor pattern 24D is connected to the terminal electrode 34, and the other end of the coil conductor pattern 25D is connected to the terminal electrode 33, so that the coil L3 and the coil L4 are balanced with the balancing terminal 12. Connected between terminals 13. The common connection end of the coil conductor pattern 24A and the coil conductor pattern 25A is connected to the terminal electrode 32, whereby the other end of the coil L3 and the other end of the coil L4 are connected to the ground. Further, the capacitor conductor pattern 26 is connected to the terminal electrode 33 and the capacitor conductor pattern 27 is connected to the terminal electrode 32, whereby the capacitor C1 is connected between the balancing terminal side of the coil L4 and the ground.

In the balun transformer thus formed, when the line width of the coil conductor pattern is 60 μm, the dielectric constant of the insulator layer is 21, and the shape of the laminate is 1.0 mm × 0.5 mm × 0.3 mm, The impedance at the unbalanced terminal is 50Ω, and the impedance at the balanced terminal is 100Ω. As shown in FIG. 4 (A), a usable frequency band of 2.4 to 2.5 GHz is obtained. As shown in (B), a phase characteristic of 180 degrees was obtained. 4A, the horizontal axis indicates frequency, the vertical axis indicates attenuation, 41 indicates insertion loss, and 42 indicates return loss. In FIG. 4B, the horizontal axis indicates frequency, the vertical axis indicates phase and amplitude, and 43. Indicates a phase characteristic, and 44 indicates a difference in magnitude of signals output from a pair of balancing terminals.
The balun transformer of the present invention has an insertion loss within the used frequency band of 0.86, a difference in signal magnitude output from one pair of balancing terminals is 0.37 dB, and is output from one pair of balancing terminals. The signal phase difference is 179.6 degrees, the return loss is 15.5 dB, the insertion loss within the operating frequency band of the conventional one is 0.9, and the difference in the magnitude of the signal output from one pair of balancing terminals is Compared to 0.54 dB, the phase difference of the signals output from one pair of balancing terminals is 178.3 degrees and the return loss is 14.8 dB, from the pair of balancing terminals in the used frequency band. The phase difference of the output signals can be improved by 1.3 degrees, and the difference in the magnitude of the signals output from the pair of balancing terminals can be improved by 0.17 dB.

It is a circuit diagram of the Example of the balun transformer of this invention. It is a disassembled perspective view which shows the Example of the balun transformer of this invention. It is a perspective view which shows the Example of the balun transformer of this invention. It is a characteristic view of the balun transformer of this invention. It is a disassembled perspective view of the conventional balun transformer. It is a circuit diagram of another conventional balun transformer.

Explanation of symbols

11 Unbalanced terminal 12 Balanced terminal 13 Balanced terminal

Claims (2)

  An insulator layer and a conductor pattern are laminated, and the first and second coils, one of which is connected in series by the conductor pattern and connected to the unbalanced terminal in the laminate, are connected to the first coil. A third coil that is electromagnetically coupled and connected between the first balancing terminal and ground, and a third coil that is electromagnetically coupled to the second coil and connected between the second balancing terminal and ground. A balun transformer comprising four coils and a capacitor connected between the second balancing terminal and ground.   An insulator layer and a conductor pattern are laminated, and the first and second coils, one of which is connected in series by the conductor pattern and connected to the unbalanced terminal in the laminate, are connected to the first coil. A third coil that is electromagnetically coupled and connected between the first balancing terminal and ground, and a third coil that is electromagnetically coupled to the second coil and connected between the second balancing terminal and ground. 4 coils and a capacitor connected between the second balancing terminal and the ground, and the capacitance of the capacitor causes a difference in magnitude of a signal output from the pair of balancing terminals and a pair of A method of adjusting the characteristics of a balun transformer, wherein a phase difference of a signal output from a balancing terminal is adjusted.

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