JP2010183192A - Phase shifter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a phase shifter which is small and ensures a required phase shift amount. <P>SOLUTION: The phase shifter is provided with first and second high frequency signal input-output terminals 1a and 1b, and at least one phase shift units 7a and 7b connected in parallel between the first and second high frequency signal input-output terminals and ground, wherein the respective phase shift units include a first inductor 3a connected between the first and second high frequency signal input-output terminals, series circuits 2a and 2b of a first switching element and a second switching element connected to the first inductor in parallel, series circuits 3b and 3c of a second inductor and a third inductor connected between a connection point of the first switching element and the second switching element, and the ground, and a third switching element 2c connected to the third inductor in parallel. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a phase shifter that changes the phase shift of a microwave.

  FIG. 10 is a circuit diagram showing a conventional phase shifter disclosed in Patent Document 1 below. This circuit includes a switching element 2f connected between a pair of high-frequency signal input / output terminals 1a and 1b, a series circuit of inductors 3d and 3e connected in parallel to the switching element 2f, a connection point between the inductors 3d and 3e, and a ground. And a switching circuit 2c connected in parallel with the inductor 3c. Then, for example, by turning on / off the switching elements 2f and 2c made of a field effect transistor (FET), the phase shifter is set to BPF (band pass filter) (2f: on, 2c: off → no phase change) or All-Pass (all Operation in the transmission state (2f: off, 2c: on → phase delay) is shown, and the required amount of phase shift is obtained by the difference in the passing phase in both states.

International Publication No. 2005/093951 Pamphlet

  In the conventional phase shifter as described above, in order to configure the circuit in a small size, it is necessary to arrange the inductors connected in parallel to each other, but when the required inductance is configured by a spiral inductor, There is a problem that it is difficult to obtain desired characteristics due to the influence of electromagnetic coupling between the two.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a phase shifter that is small and can obtain a required amount of phase shift.

  The present invention includes first and second high-frequency signal input / output terminals, and at least one phase shift unit connected in parallel between the first and second high-frequency signal input / output terminals and the ground, Each phase shift unit includes a first inductor connected between the first and second high-frequency signal input / output terminals, a first switching element and a second switching element connected in parallel to the first inductor. Series circuit, a series circuit of a second inductor and a third inductor connected between the connection point of the first switching element and the second switching element and the ground, and a parallel connection to the third inductor The phase shifter includes a third switching element.

  According to the present invention, it is possible to provide a phase shifter that is small and can obtain a required amount of phase shift.

It is a circuit diagram which shows the structure of the phase shifter by Embodiment 1 of this invention. It is a figure which shows the equivalent circuit in the 1st state of the phase shifter of FIG. It is a figure which shows the equivalent circuit in the 2nd state of the phase shifter of FIG. It is a circuit diagram which shows the structure of the phase shifter by Embodiment 2 of this invention. It is a figure which shows the equivalent circuit in the 1st state of the phase shifter of FIG. It is a figure which shows the equivalent circuit in the 2nd state of the phase shifter of FIG. It is a circuit diagram which shows the structure of the phase shifter by Embodiment 3 of this invention. It is a circuit diagram which shows the structure of the phase shifter by Embodiment 4 of this invention. It is a circuit diagram which shows the structure of the phase shifter by Embodiment 5 of this invention. It is a circuit diagram which shows the structure of the conventional phase shifter.

Embodiment 1 FIG.
1 is a circuit diagram showing a configuration of a phase shifter according to Embodiment 1 of the present invention. In FIG. 1, at least one phase shift unit 7a, 7b (see FIG. 9) is connected in parallel between a pair of first and second high-frequency signal input / output terminals 1a, 1b and the ground. FIG. 1 shows one phase shift unit (the same applies to FIGS. 1 to 8). The phase shift unit includes a first inductor 3a connected between the first and second high-frequency signal input / output terminals 1a and 1b, A series circuit of the first switching element 2a and the second switching element 2b connected in parallel to the first inductor 3a, and between the connection point of the first switching element 2a and the second switching element 2b and the ground. A series circuit of a second inductor 3b and a third inductor 3c connected, and a third switching element 2c connected in parallel to the third inductor 3c are provided. The first to third switching elements 2a to 2c are made of, for example, field effect transistors (FETs) (the same applies hereinafter).

  Next, the operation of the circuit of FIG. 1 will be described. The first to third switching elements 2a to 2c can be equivalently regarded as resistors at high frequencies when the switch is closed, and can be regarded as equivalently capacitors when the switch is open. FIG. 2 shows an equivalent circuit in a first state in which the first and second switching elements 2a and 2b of the circuit of FIG. 1 are closed and the third switching element 2c is opened. 50a and 50b are equivalent resistances of the closed first and second switching elements 2a and 2b, and 40c is a capacitor equivalently of the opened third switching element 2c. Here, when the resistance values of the resistors 50a and 50b are sufficiently small, this circuit can be regarded as a circuit composed of the second and third inductors 3b and 3c and the capacitor 40c. Operate.

  FIG. 3 shows an equivalent circuit in the second state in which the first and second switching elements 2a and 2b of the circuit of FIG. 1 are opened and the third switching element 2c is closed. Reference numerals 40a and 40b denote capacitors equivalent to the opened first and second switching elements 2a and 2b, and reference numeral 50c denotes a resistor equivalent to the closed third switching element 2c. Here, when the resistance value of the resistor 50c is sufficiently small, the circuit operates as an All-Pass circuit including the second and third inductors 3b and 3c and the capacitors 40a and 40b.

  As described above, since the operation as a BPF or All-Pass circuit is shown by opening and closing of the switching element, a required amount of phase shift can be obtained by the difference in these passing phases.

In this way, switching between the BPF and the All-Pass circuit can be performed. Furthermore, since the inductors are not adjacent to each other, good characteristics can be obtained with little characteristic deterioration due to electromagnetic coupling.
In addition, the conventional inductors 3d and 3e connected in parallel do not have a freedom of layout at the position where the inductors are arranged, and it is necessary to arrange them adjacent to each other in order to achieve a small size. Since the inductors 3b and 3c connected in series in FIG. 1 and the like have a degree of freedom in layout at the position where the inductors are arranged, deterioration of characteristics can be prevented by arranging them separately.

Embodiment 2. FIG.
4 is a circuit diagram showing a configuration of a phase shifter according to Embodiment 2 of the present invention. In FIG. 4, the same or corresponding parts as those in the above embodiment are denoted by the same reference numerals, and description thereof is omitted. The phase shifter (phase shift unit) shown in FIG. 4 is the connection point between the first high frequency signal input / output terminal 1a side, the first inductor 3a, and the first switching element 2a in the phase shifter of FIG. Connected between the fourth switching element 2d, the second high-frequency signal input / output terminal 1d side, and the connection point between the first inductor 3a and the second switching element 2b. And a fifth switching element 2e.

  FIG. 5 shows an equivalent circuit in the first state in which the first and second switching elements 2a and 2b of the circuit of FIG. 4 are closed and the third to fifth switching elements 2c, 2d and 2e are opened. Reference numerals 50a and 50b denote equivalent resistances of the closed first and second switching elements 2a and 2b, and reference numerals 40c, 40d and 40e denote equivalent capacitors of the opened third to fifth switching elements 2c, 2d and 2e. It is. Here, when the resistance values of the resistors 50a and 50b are sufficiently small, this circuit can be regarded as a circuit including the second and third inductors 3b and 3c and the capacitors 40c, 40d, and 40e. The circuit operates as a BPF.

  FIG. 6 shows an equivalent circuit in the second state in which the first and second switching elements 2a and 2b of the circuit of FIG. 4 are opened and the third to fifth switching elements 2c, 2d and 2e are closed. Reference numerals 40a and 40b denote capacitors equivalent to the opened first and second switching elements 2a and 2b, and reference numerals 50c, 50d and 50e denote equivalent resistances to the closed third to fifth switching elements 2c, 2d and 2e. It is. Here, when the resistance values of the resistors 50c, 50d, and 50e are sufficiently small, this circuit can be regarded as a circuit including the second and third inductors 3b and 3c and the capacitors 40a and 40b. The circuit operates as an All-Pass circuit.

  As described above, since the operation as the capacitively coupled BPF or the All-Pass circuit is shown by opening and closing the switching element, a required amount of phase shift can be obtained by the difference in the passing phase.

  In this way, the first state can be a broadband capacitively coupled BPF circuit while maintaining the operation as a broadband All-Pass circuit, and as a result, broadband characteristics are obtained in both states.

Embodiment 3 FIG.
7 is a circuit diagram showing a configuration of a phase shifter according to Embodiment 3 of the present invention. In FIG. 7, the same or corresponding parts as those in the above embodiment are denoted by the same reference numerals, and description thereof is omitted. The phase shifter (phase shift unit) shown in FIG. 7 has a configuration in which resistors 5a and 5b are respectively connected in parallel to the fourth and fifth switching elements 2d and 2e in the phase shifter of the second embodiment shown in FIG. is there.

  In this case, in the first state in which the fourth and fifth switching elements 2d and 2e are opened, the switching elements 2d and 2e have losses due to the resistors 5a and 5b.

  In this way, the loss of the circuit in the first state can be arbitrarily determined, so this can be made equal to the loss of the circuit in the second state, and the loss difference between the first and second states can be It becomes possible to reduce.

  Further, even when a resistor is connected in parallel to the first to third switching elements 2a, 2b, and 2c, the same effect as described above can be obtained.

Embodiment 4 FIG.
FIG. 8 is a circuit diagram showing a configuration of a phase shifter according to Embodiment 4 of the present invention. In FIG. 8, the same or corresponding parts as those in the above embodiment are designated by the same reference numerals and the description thereof is omitted. The phase shifter (phase shift unit) shown in FIG. 8 has a configuration in which capacitors 4a and 4b are connected in parallel to the fourth and fifth switching elements 2d and 2e in the phase shifter of the second embodiment shown in FIG. is there.

  Thus, in the state where the fourth and fifth switching elements 2d and 2e are opened, the combined capacity of the capacitor 40d and the capacitor 4a equivalent to the switching element 2d and the capacitor 40e equivalent to the switching element 2e and The combined capacitance of the capacitor 4b is equivalent to the capacitance value of the capacitor that is equivalent when the switching element 2d of the phase shifter according to the second embodiment is open and the capacitance value of the capacitor that is equivalent when the switching element 2e is open. Assume that they are set to be equal.

  Thereby, since the capacitor which equivalent to a switching element can be made small, the physical dimension of this switching element can be made small, and the miniaturization of a circuit is attained as a result.

  Further, even when a capacitor is connected in parallel to the first to third switching elements 2a, 2b, 2c, the same effect as described above can be obtained.

Embodiment 5 FIG.
FIG. 9 is a circuit diagram showing a configuration of a phase shifter according to Embodiment 5 of the present invention. In FIG. 9, the same or corresponding parts as those in the above embodiment are denoted by the same reference numerals, and description thereof is omitted. In FIG. 9, reference numerals 7a and 7b denote single bit phase shifters corresponding to the phase shift units shown in FIGS. Here, an example is shown in which the phase shifter according to the first embodiment of the present invention shown in FIG. 1 is used as the single bit phase shifters 7a and 7b.

  Thus, by connecting the plurality of single-bit phase shifters 7a and 7b in parallel between the first and second high-frequency signal input / output terminals 1a and 1b and the ground, a desired amount of phase shift is obtained discretely. It becomes possible to operate as a multi-bit phase shifter.

  In each of the above embodiments, the case where a field effect transistor is used as the switching element has been described. However, the same effect can be obtained even when a switching element such as a bipolar transistor, a PIN diode, a varactor diode, or a MEMS switch is used. It is done.

  Further, the present invention is not limited to the above-described embodiments, and it goes without saying that all possible combinations thereof are included.

  1a, 1b High-frequency signal input / output terminals, 2a-2e switching elements, 3a-3c inductors, 4a, 4b, 40a-40e capacitors, 5a, 5b, 50a-50e resistors, 6 grounds, 7a, 7b single-bit phase shifters ( Phase shift unit).

Claims (5)

First and second high-frequency signal input / output terminals (1a, 1b);
At least one phase shift unit (7a, 7b) connected in parallel between the first and second high-frequency signal input / output terminals and the ground;
Each of the phase shifting units comprises:
A first inductor (3a) connected between the first and second high-frequency signal input / output terminals;
A series circuit (2a, 2b) of a first switching element and a second switching element connected in parallel to the first inductor;
A series circuit (3b, 3c) of a second inductor and a third inductor connected between a connection point between the first switching element and the second switching element and the ground;
A third switching element (2c) connected in parallel to the third inductor;
including,
A phase shifter characterized by that. Each phase shifter unit is
A fourth switching element (2d) connected between the first high-frequency signal input / output terminal side and a connection point between the first inductor and the first switching element;
A fifth switching element (2e) connected between the second high-frequency signal input / output terminal side and a connection point between the first inductor and the second switching element;
The phase shifter according to claim 1, further comprising:   The phase shifter according to claim 1 or 2, wherein a resistor (5a, 5b) is connected in parallel to at least one of the first to fifth switching elements.   The phase shifter according to any one of claims 1 to 3, wherein a capacitor (4a, 4b) is connected in parallel to at least one of the first to fifth switching elements.   5. A multi-bit phase shifter comprising a plurality of phase shift units (7a, 7b) connected between the first and second high-frequency signal input / output terminals. The phase shifter according to item 1.

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