WO2018138829A1 - High frequency branching filter and high frequency circuit using same - Google Patents

Abstract

A 90-degree hybrid circuit (2) outputs radio waves of a first frequency from a fourth terminal (24) thereof and outputs radio waves of a second frequency from a third terminal (23) thereof. A phase shifting circuit (3), with respect to the first frequency, feeds a second terminal (22) with radio waves having a phase delay of 90 degrees relative to radio waves fed to a first terminal (21), and, with respect to the second frequency, feeds the second terminal (22) with radio waves with a phase advance of 90 degrees relative to the radio waves fed to the first terminal (21).

Description

High frequency demultiplexer and high frequency circuit using the same

The present invention relates to a high-frequency demultiplexer that demultiplexes radio waves having a plurality of input frequencies, and a high-frequency circuit using the same.

As a conventional high frequency demultiplexer, there is a configuration using a plurality of band pass filters (see, for example, Patent Document 1). This high-frequency demultiplexer has a configuration in which band-pass filters having passbands of second, third, and fourth harmonics are connected in parallel. In this high frequency demultiplexer, when a radio wave including harmonics is input to the high frequency demultiplexer, a frequency corresponding to the pass frequency band of the band pass filter is output from a separate terminal.

JP-A-8-65050

However, the conventional high frequency demultiplexer requires a plurality of filters, which increases the size and does not satisfy the demand for miniaturization.

The present invention has been made to solve such a problem, and an object of the present invention is to provide a high frequency demultiplexer that can be miniaturized.

The high frequency branching filter according to the present invention includes first to fourth terminals. When the first terminal is an input terminal, the second terminal is an isolation terminal, the third terminal is a 0 ° output terminal, The fourth terminal is a 90 ° hybrid circuit that has a relationship of being a −90 ° output terminal, and of the input radio waves, the first frequency is a radio wave having a phase delayed by 90 ° relative to the radio wave applied to the first terminal. Is provided to the second terminal, and with respect to the second frequency, there is provided a phase shift circuit for providing the second terminal with a radio wave having a phase advanced by 90 ° relative to the radio wave provided to the first terminal.

A high frequency duplexer according to the present invention includes a 90 ° hybrid circuit having first and second terminals to which radio waves having a first frequency and a second frequency are input, and a first frequency input to the second terminal. The first frequency radio wave is delayed by 90 ° from the first frequency radio wave input to the first terminal, and the second frequency radio wave input to the second terminal is input to the first terminal. The phase is 90 degrees ahead of the second frequency radio wave. Thereby, the radio waves of the first frequency and the second frequency can be demultiplexed without using a plurality of filters, and the size can be reduced.

It is a block diagram of the high frequency branching filter of Embodiment 1 of this invention. It is a block diagram at the time of providing the open stub in the 4th terminal of the high frequency branching filter of Embodiment 1 of this invention. It is a block diagram at the time of opening the 4th terminal of the high frequency branching filter of Embodiment 1 of this invention. It is a block diagram at the time of providing the short stub in the input terminal of the high frequency branching filter of Embodiment 1 of this invention. It is a block diagram at the time of providing the short stub and the resistance in the input terminal of the high frequency branching filter of Embodiment 1 of this invention. It is a block diagram which shows the high frequency circuit of Embodiment 2 of this invention. It is a block diagram which shows the high frequency circuit of Embodiment 3 of this invention. It is a block diagram which shows the high frequency circuit of Embodiment 4 of this invention.

Hereinafter, in order to explain the present invention in more detail, modes for carrying out the present invention will be described with reference to the accompanying drawings.
Embodiment 1 FIG.
FIG. 1 is a configuration diagram of a high frequency demultiplexer according to the present embodiment.
As shown in FIG. 1, the high frequency branching filter according to the present embodiment includes an input terminal 100, a phase shift circuit 3 that equally distributes high frequency power input from the input terminal 100, and provides a phase difference. A 90 ° hybrid circuit 2 having fourth terminals 21, 22, 23, and 24 is provided. The phase shift circuit 3 equally distributes the high frequency input to the input terminal 100 by the in-phase distributor 31, gives one output to the first terminal 21 of the 90 ° hybrid circuit 2, and supplies the other output to the fundamental wave. Is applied to the second terminal 22 of the 90 ° hybrid circuit 2 through the transmission line 32 having a quarter wavelength. Here, when the first terminal 21 of the 90 ° hybrid circuit 2 is an input (IN) terminal, the second terminal 22 is an isolation (ISO) terminal, the third terminal 23 is a 0 ° output terminal, and the fourth terminal The terminal 24 is in the relationship of being a −90 ° output terminal. The 90 ° hybrid circuit 2 is composed of, for example, a Lange coupler.

Next, the operation of the high frequency demultiplexer according to the first embodiment will be described.
The fundamental wave, which is the first frequency and the third harmonic wave, which is the second frequency, input from the input terminal 100 are divided into two at the same amplitude by the in-phase distributor 31 in the phase shift circuit 3. One output of the in-phase distributor 31 is input to the first terminal 21 of the 90 ° hybrid circuit 2, and the other output of the in-phase distributor 31 is 90 ° via a transmission line 32 having a fundamental wavelength of ¼ wavelength. The signal is input to the second terminal 22 of the hybrid circuit 2. At this time, the fundamental wave input to the second terminal 22 of the 90 ° hybrid circuit 2 is 90 ° out of phase with the fundamental wave input to the first terminal 21, and is input to the second terminal 22. The third harmonic wave is 90 ° ahead of the third harmonic wave input to the first terminal 21.

The 90 ° hybrid circuit 2 shifts the high frequency input to the first terminal 21 by θ and outputs it from the third terminal 23, and shifts by θ−90 ° and outputs it from the fourth terminal 24. Similarly, the high frequency input to the second terminal 22 is phase-shifted by θ and output from the fourth terminal 24, and phase-shifted by −90 ° and output from the third terminal 23. Here, for simplicity of explanation, θ is set to 0 °.

The fundamental wave inputted to the first terminal 21 of the 90 ° hybrid circuit 2 and the fundamental wave delayed by 90 ° inputted to the second terminal 22 are not outputted at the third terminal 23 due to the reverse phase synthesis. 4 terminal 24 outputs in-phase synthesis. On the other hand, the third harmonic wave input to the first terminal 21 and the third harmonic wave advanced by 90 ° input to the second terminal 22 are not output in the fourth terminal 24 and are not output. At the terminal 23, in-phase synthesis is performed and output.
Therefore, the fundamental wave and the third harmonic wave input to the input terminal 100 are demultiplexed and output from the fourth terminal 24 and the third terminal 23, respectively.

In the above description, the first frequency is the fundamental wave, and the second frequency is the third harmonic. However, the phase shift circuit 3 similarly applies the second frequency to the second terminal 22 of the 90 ° hybrid circuit 2 at other frequencies. The phase of the first frequency radio wave input is delayed by 90 ° from the first frequency radio wave input to the first terminal 21 and the phase of the second frequency radio wave input to the second terminal 22 is delayed. Can be demultiplexed by advancing the phase by 90 ° relative to the radio wave of the second frequency input to the first terminal 21.

Further, as shown in FIG. 2, the fourth terminal 24 of the 90 ° hybrid circuit 2 is provided with an open stub 40 having a quarter wavelength of the fundamental wave, so that the third harmonic wave demultiplexed at the third terminal 23 is obtained. The fundamental wave can be reflected back to the input terminal 100 without affecting the signal. In addition, as shown in FIG. 3, even if the fourth terminal 24 of the 90 ° hybrid circuit 2 is opened, the fundamental wave is reflected to the input terminal 100 without affecting the third harmonic wave. Can be returned. Thus, by reflecting the fundamental wave back to the input terminal 100, for example, when a high frequency demultiplexer is applied as one of the feedback circuits of the oscillator, the loop gain can be improved and the output frequency can be increased. There is an effect that can be.

Furthermore, as shown in FIG. 4, the input terminal 100 may be provided with a short stub 41 having a fundamental wavelength of ¼ wavelength. As a result, the second harmonic wave can be reflected without affecting the fundamental wave and the third harmonic wave, and the input of the second harmonic wave can be suppressed and separated. For example, when a high frequency demultiplexer is applied to an oscillator, a fundamental wave, a second harmonic wave, and a third harmonic wave are output from the oscillator. Here, when it is desired to extract the fundamental wave and the third harmonic wave, since the output of the second harmonic wave is unnecessary, this can be suppressed as an input, and emission of unnecessary waves can be suppressed.

Further, as shown in FIG. 5, the input terminal 100 may be provided with a short stub 41 and a resistor 42 having a fundamental wave of ¼ wavelength. The resistor 42 is connected to one end of the short stub 41 that opens the fundamental wave. As a result, the second harmonic can be attenuated without affecting the fundamental wave and the third harmonic, the input of the second harmonic can be suppressed, and the emission of unnecessary waves can be suppressed.

As described above, according to the high frequency demultiplexer of the first embodiment, when the first to fourth terminals are provided and the first terminal is an input terminal, the second terminal is an isolation terminal, The third terminal is a 0 ° output terminal, the fourth terminal is a -90 ° output terminal, and the 90 ° hybrid circuit, and the radio wave applied to the first terminal with respect to the first frequency among the input radio waves. A phase shift circuit that applies to the second terminal radio waves that are delayed by 90 ° relative to the second terminal, and applies to the second terminals radio waves that are advanced by 90 ° relative to radio waves that are applied to the first terminal with respect to the second frequency. Therefore, the radio waves of the first frequency and the second frequency can be demultiplexed without using a plurality of filters, and the size can be reduced.

Further, according to the high frequency demultiplexer of the first embodiment, the first frequency is the fundamental wave, the second frequency is the third harmonic, and the phase shift circuit converts the fundamental wave and the third harmonic to the first frequency. An in-phase distributor that distributes to the terminal and the second terminal at the same phase and with equal amplitude; and an electric length between the in-phase distributor and the first terminal, provided between the in-phase distributor and the second terminal. Since a transmission line having a quarter wavelength longer than the fundamental wave is also provided, the fundamental wave and the third harmonic wave can be demultiplexed and output.

In addition, according to the high frequency demultiplexer of the first embodiment, the fourth terminal is provided with the open stub having a ¼ wavelength at the first frequency, so that the demultiplexed third harmonic is affected. Instead, the fundamental wave can be reflected back to the input terminal of the high frequency demultiplexer.

Further, according to the high frequency demultiplexer of the first embodiment, since the short stub having a quarter wavelength at the first frequency is provided at the input terminal of the high frequency demultiplexer or the phase shift circuit, the fundamental wave and 3 The second harmonic wave is reflected without affecting the second harmonic wave, and the input of the second harmonic wave can be suppressed and separated.

Further, according to the high frequency demultiplexer of the first embodiment, since the resistor is provided at the tip that is open at the first frequency of the short stub, the second harmonic wave can be generated without affecting the fundamental wave and the third harmonic wave. It is possible to attenuate and suppress the input of the second harmonic.

Embodiment 2. FIG.
FIG. 6 is a configuration diagram showing a high frequency amplifier using the high frequency demultiplexer of the first embodiment as the high frequency circuit of the second embodiment.
In FIG. 6, the high frequency demultiplexer 1a is the high frequency demultiplexer shown in FIG. 4 of the first embodiment, and the corresponding parts are denoted by the same reference numerals and description thereof is omitted. The input terminal 100 in the high frequency demultiplexer 1a is configured to be supplied with the output of the amplifier 5, and the third terminal 23 of the 90 ° hybrid circuit 2 in the high frequency demultiplexer 1a has a third wavelength and a quarter wavelength. An open stub 43 is provided.

Next, the operation of the second embodiment will be described.
The operation of the high frequency demultiplexer 1a is the same as that of the first embodiment. However, in the high frequency demultiplexer 1a shown in FIG. 6, the short wave is short-circuited and reflected by the short stub 41 independently of the fundamental wave and the third harmonic wave, and is reflected by the open stub 43 independently of the fundamental wave and the second harmonic wave. The third harmonic wave can be reflected and returned to the input terminal 100. Therefore, the phase of the second harmonic can be designed independently from the electrical length from the amplifier 5 to the short stub 41, and the phase of the third harmonic from the electrical length from the amplifier 5 to the open stub 43 can be designed independently.

As described above, in the high-frequency circuit of the second embodiment, the fundamental wave, the second harmonic, and the third harmonic can be designed independently, so that the harmonic processing becomes easy. That is, in the harmonic processing, a fundamental wave, a harmonic wave such as a second harmonic wave and a third harmonic wave are combined to form a desired waveform. At that time, these phase relationships are important. For example, when the fundamental wave and the third harmonic wave are combined in phase, the shape approaches a rectangle. The waveform collapses. Therefore, harmonic processing or waveform formation is facilitated by the fact that the fundamental and harmonic phases can be designed independently.

As described above, according to the high frequency circuit of the second embodiment, an amplifier is connected to the input terminal of the high frequency branching filter or phase shift circuit of the first embodiment, and the third terminal is connected to the second frequency. Since an open stub having a quarter wavelength is provided, harmonic processing can be easily performed, and power consumption of the amplifier can be improved.

Embodiment 3 FIG.
FIG. 7 is a configuration diagram showing a high frequency oscillator using the high frequency demultiplexer of the first embodiment as the high frequency circuit of the third embodiment.
In FIG. 7, the high-frequency demultiplexer 1 is the high-frequency demultiplexer shown in FIG. 1. The drain terminal of the transistor 60 is connected to the input terminal 100 in the high frequency demultiplexer 1, and the fourth terminal 24 in the high frequency demultiplexer 1 is open. The transistor 60 includes a feedback circuit 61 and a feedback circuit 62 at its source terminal and gate terminal, respectively.

Next, the operation of the third embodiment will be described.
The operation of the high frequency demultiplexer 1 is the same as the operation of the configuration shown in FIG. However, the high frequency demultiplexer 1 shown in FIG. 7 operates as one of the feedback circuits of the oscillator, and the fundamental wave reflected by the fourth terminal 24 of the 90 ° hybrid circuit 2 returns to the input terminal 100, and the transistor 60. In the high frequency oscillator of the third embodiment, the fundamental wave is fed back in series. The high frequency (initially noise) input to the gate terminal of the transistor 60 is amplified by the transistor 60 and output to the drain terminal, and the high frequency reflected by the drain terminal side circuit (here, the high frequency demultiplexer 1) is the transistor 60. The signal is input to the feedback circuit 61 through the drain-source and reflected from the source. Further, the signal is input to the feedback circuit 62 via the gate and source of the transistor 60, reflected, and fed back to the gate terminal of the transistor 60 so as to be in phase. This high frequency becomes the oscillation frequency.

In order for the oscillator to oscillate, it is necessary that the gain obtained by making a circuit of the transistor and the feedback circuit connected to each terminal of the transistor is positive, and the larger one is easier to oscillate. The high-frequency oscillator shown in FIG. 7 feeds back the fundamental wave for performing the oscillation operation to the transistor 60 without outputting it to an external load. Therefore, the loop gain of the oscillator is improved and the oscillator can easily perform the oscillation operation. Further, the third harmonic wave obtained by the oscillation operation is output from the third terminal 23 of the 90 ° hybrid circuit 2.
Here, an example is shown in which the high frequency demultiplexer is connected to the drain terminal as one of the feedback circuits, but the high frequency demultiplexer may be provided at the gate terminal or the source terminal.

As described above, according to the high frequency circuit of the third embodiment, the input terminal of the high frequency duplexer of the first embodiment configured as a feedback circuit is connected to at least one of the transistor terminals, and the oscillation Since the operation is performed, the fundamental wave that performs the oscillating operation by the high frequency demultiplexer can be fed back and the third harmonic wave that is the harmonic thereof can be output, so that the oscillating operation can be easily realized. In addition, phase noise can be improved because transistors and resonators having better performance can be used than when the oscillator is configured with a frequency corresponding to the third harmonic directly. This is because the loss is lower and the parasitic component is smaller when the low frequency is handled.

Further, according to the high frequency circuit of the third embodiment, since the fourth terminal is opened, the fundamental wave is applied to the input terminal of the high frequency demultiplexer without affecting the demultiplexed third harmonic. It can be reflected back.

Embodiment 4 FIG.
FIG. 8 is a configuration diagram showing a PLL synthesizer using the high frequency demultiplexer of the first embodiment as the high frequency circuit of the fourth embodiment.
In FIG. 8, the high-frequency demultiplexer 1 is the high-frequency demultiplexer shown in FIG. A voltage controlled oscillator (VCO) 70 of a phase locked loop (PLL) is connected to the input terminal 100 in the high frequency demultiplexer 1, and the fundamental wave output from the fourth terminal 24 of the 90 ° hybrid circuit 2 is a PLL circuit unit. 71, and the output of the PLL circuit unit 71 is given to the voltage controlled oscillator 70 to perform negative feedback control. Here, the PLL circuit unit 71 is a circuit configured by a phase comparator, a reference oscillator, a loop filter, a prescaler, and the like, and the voltage controlled oscillator 70 and the PLL circuit unit 71 configure a known phase synchronization circuit. .

Next, the operation of the fourth embodiment will be described.
The operation of the high frequency demultiplexer 1 is the same as that of the first embodiment. The voltage controlled oscillator 70 is a circuit whose oscillation frequency changes by controlling the voltage, and performs an oscillation operation with a fundamental wave. The fundamental wave output from the voltage controlled oscillator 70 is output from the fourth terminal 24 of the 90 ° hybrid circuit 2 via the high frequency duplexer 1. The fundamental wave output from the fourth terminal 24 is phase-compared with the reference frequency output from the reference oscillator in the PLL circuit unit 71, and the PLL circuit unit 71 supplies the voltage controlled oscillator 70 with a voltage corresponding to the phase error. The voltage controlled oscillator 70 corrects the oscillation frequency according to the applied voltage. The third harmonic generated by this oscillation operation is not output from the fourth terminal 24 of the 90 ° hybrid circuit 2 but is output from the third terminal 23.

As described above, according to the high frequency circuit of the fourth embodiment, the output of the fourth terminal of the high frequency demultiplexer of the first embodiment includes the phase synchronization circuit that inputs the radio wave for phase comparison with the reference frequency, Since the output of the voltage controlled oscillator of the phase locked loop is connected to the input terminal of the high frequency demultiplexer, the following effects are obtained. That is, a fundamental wave that oscillates with a high frequency demultiplexer connected to the output of the oscillator and its third harmonic are demultiplexed, the fundamental wave is input to the phase locked loop, and the third harmonic is output to the outside By doing so, the prescaler used in the phase synchronization circuit can be reduced or the frequency dividing number can be reduced, and the PLL synthesizer can be downsized and the phase noise can be improved. Further, as in the third embodiment, since a transistor or a resonator having better performance can be used than when the oscillator is configured directly at a frequency corresponding to the third harmonic, the effect of improving the phase noise of the oscillator is achieved.

In the present invention, within the scope of the invention, any combination of the embodiments, or any modification of any component in each embodiment, or omission of any component in each embodiment is possible. .

As described above, the high frequency demultiplexer and the high frequency circuit according to the present invention relate to a configuration of a high frequency demultiplexer that demultiplexes radio waves having a plurality of input frequencies and a high frequency circuit using the high frequency demultiplexer. It is suitable for use in high frequency amplifiers, high frequency oscillators, PLL synthesizers and the like.

1, 1a High frequency demultiplexer, 2 90 ° hybrid circuit, 3 phase shift circuit, 5 amplifier, 21 1st terminal, 22 2nd terminal, 23 3rd terminal, 24 4th terminal, 31 in-phase distributor , 32 transmission lines, 40, 43 open stubs, 41 short stubs, 42 resistors, 60 transistors, 61, 62 feedback circuits, 70 voltage controlled oscillators, 71 PLL circuit units, 100 input terminals.

Claims (9)

When the first terminal is an input terminal, the second terminal is an isolation terminal, the third terminal is a 0 ° output terminal, and the fourth terminal is − A 90 ° hybrid circuit in a relationship to become a 90 ° output terminal;
Of the input radio waves, with respect to the first frequency, a radio wave having a phase delayed by 90 ° with respect to the radio wave applied to the first terminal is applied to the second terminal, and the first frequency is related to the first frequency. A high-frequency branching filter comprising: a phase shift circuit that applies, to the second terminal, a radio wave having a phase advanced by 90 ° with respect to the radio wave applied to the terminal. The first frequency is a fundamental wave, and the second frequency is a third harmonic,
The phase shift circuit, the in-phase distributor for distributing the fundamental wave and the third harmonic wave to the first terminal and the second terminal with the same phase and equal amplitude;
A transmission line that is provided between the in-phase distributor and the second terminal and that is 1/4 wavelength longer in the fundamental wave than the electrical length between the in-phase distributor and the first terminal; The high frequency demultiplexer according to claim 1, wherein: 2. The high frequency demultiplexer according to claim 1, wherein an open stub having a quarter wavelength at the first frequency is provided at the fourth terminal. The high frequency demultiplexer according to claim 1, wherein a short stub having a quarter wavelength at the first frequency is provided at an input terminal of the phase shift circuit. 5. The high frequency demultiplexer according to claim 4, wherein a resistor is provided at a tip of the short stub that opens at the first frequency. The high frequency demultiplexer according to claim 4, wherein an amplifier is connected to an input terminal of the phase shift circuit, and an open stub having a quarter wavelength at the second frequency is provided at the third terminal. A featured high-frequency circuit. 2. A high-frequency circuit characterized in that at least one of the terminals of the transistor is connected to an input terminal of the high-frequency demultiplexer according to claim 1 configured as a feedback circuit to perform an oscillation operation. The high-frequency circuit according to claim 7, wherein the fourth terminal is open. A high frequency demultiplexer according to claim 1, further comprising a phase synchronization circuit for inputting an output of the fourth terminal of the high frequency demultiplexer as a radio wave for phase comparison with a radio wave of a reference frequency, A high frequency circuit characterized in that an output of a voltage controlled oscillator is connected to an input terminal of the high frequency demultiplexer.

Images