JP4678076B2 - Resonator, oscillator, filter, duplexer, and communication device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a resonator using a stripline or a microstripline, an oscillator, a filter, a duplexer, and a communication device including them.
[0002]
[Prior art]
Conventionally, a voltage controlled oscillator (VCO) in a microwave band is configured as a band reflection type oscillator by providing a resonator by a microstrip line on a dielectric plate and connecting a negative resistance circuit to the resonator. . In order to control the oscillation frequency by voltage control, a variable capacitance element such as a varicap diode is loaded on the resonator by the microstrip line, and the resonance frequency of the resonator is changed by a control voltage applied from the outside, thereby The oscillation frequency was controlled.
[0003]
Therefore, the variable range of the oscillation frequency is determined by the capacitance change range of the variable capacitance diode. If a variable capacitor with a large capacitance change ratio is used, the frequency variable range can be increased accordingly, but in general, a varicap diode with a large capacitance change ratio is used. Since the equivalent series resistance is large, the C / N ratio characteristic is deteriorated. In addition, the frequency variable range can be widened by widening the voltage variable range, but the linearity of the oscillation frequency change with respect to the control voltage change is deteriorated.
[0004]
Therefore, when the frequency variable range is widened, the resonance frequency of the resonance line is switched by a diode switch as shown in FIG. In the example shown in FIG. 9A, the variable capacitance element DV1 and the oscillation circuit are connected to the resonance lines S1 and S2 by the microstrip line, and a control voltage supply circuit by the inductor L1 and the capacitor C1 is provided for the variable capacitance element DV1. Thus, a voltage controlled oscillator is constituted as a whole. The resonance lines S1 and S2 are connected via a diode D1, and a voltage signal for band switching is given to the diode D1 via an RF signal blocking circuit including an inductor L2 and a capacitor C2. With this configuration, the diode D1 is turned on / off by the bias voltage applied to the band switching terminal, and the resonance length of the resonance line of the microstrip line is switched to change the resonance frequency.
[0005]
In the example shown in FIG. 9B, the capacitor C3 and C4 are connected to the resonance line S1 of the microstrip line, and the diode D1 is connected in parallel to C4, and the bias voltage for the band switching terminal is taken. Thus, the diode D1 is turned on / off, whereby the capacitance added to the open end of the resonance line S1 is switched to switch the resonance frequency.
[0006]
[Problems to be solved by the invention]
However, when a diode is used to switch the resonance frequency of the resonance line in this way, the loss of the resonator increases due to the equivalent series resistance of the diode, and the C / N ratio deteriorates as compared with the case without the diode. there were.
[0007]
An object of the present invention is to enable a resonator that widens the variable range of the resonance frequency and prevents the Q from being lowered, an oscillator that widens the variable range of the oscillation frequency and prevents the deterioration of the C / N ratio, and frequency characteristics can be switched. It is another object of the present invention to provide a filter, a duplexer, and a communication device using the same, which achieve low loss.
[0008]
[Means for Solving the Problems]
Resonator of the present invention is by strip line or microstrip line on a dielectric plate, a different Do that two resonant lines of the resonant frequency provided, provided line switch movable portion for selectively turned into the two resonant lines A resonator,
The dielectric plate has an inner surface on which open ends of the two resonance lines are formed,
The line switching movable portion is disposed between the open ends of the two resonance lines in a space surrounded by the inner surface in the dielectric plate.
[0009]
In this way, by selectively conducting the two resonant lines with the line switching movable part, the line can be conducted with a resistance lower than the equivalent series resistance of the diode, and the decrease in the Q of the resonator can be suppressed.
[0010]
In the resonator according to the present invention, the drive source of the line switching movable part is a piezoelectric element. The drive source of the movable section for switching lines is composed of a coil and a movable magnetic piece.
[0011]
Oscillator of the present invention is constructed by connecting a negative resistance circuits to the resonator.
[0012]
The filter according to the present invention includes a transmission line connected between an input terminal and an output terminal, and the resonator, and connects the line switching movable portion to the transmission line of the resonator, The end opposite to the open end is grounded to configure.
[0013]
Duplexer of the present invention, receives one filter, as transmission filter while the filter 2 Kumisonae stopband of the reception filter is a transmission signal band, stop band of the transmission filter Ru received signal band der Shall .
[0014]
Furthermore, the communication device of the present invention is configured using the resonator, the oscillator, the filter, or the duplexer.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
The configuration of the voltage controlled oscillator according to the first embodiment of the present invention will be described with reference to FIG. 1 and FIG.
FIG. 1 is a circuit diagram thereof. Here, reference numerals 2a and 2b denote resonant lines using microstrip lines, the line lengths of which are different from each other, and their resonant frequencies are set to predetermined values. Reference numeral 3 denotes a line switching movable portion. Depending on the state of the line switching movable portion, either one of the resonance lines 2a or 2b is connected to the oscillation circuit. The oscillation circuit includes an FET exhibiting negative resistance characteristics, a bias voltage supply circuit for the FET, and the like. DV1 is a variable capacitance diode and is connected in parallel to the resonance lines 2a and 2b. The inductor L1 and the capacitor C1 block the RF signal and supply a control voltage to the variable capacitance diode DV1.
[0016]
FIG. 2 is a partial perspective view showing the configuration of the voltage variable oscillator. Here, 1 is a dielectric plate, and resonance lines 2a and 2b by microstrip lines are formed on the upper surface thereof. A substantially entire ground electrode is formed on the lower surface of the dielectric plate 1. The end connected in common to the two resonance lines 2a and 2b is connected to the ground electrode on the lower surface through a through hole. (The connection to the ground electrode is represented by a ground symbol in the figure.) Further, on the upper surface of the dielectric plate 1, a microstrip line 4 that acts as a part of the resonance line and is connected to the oscillation circuit is provided. Forming. A line switching movable portion 3 is provided between the microstrip line 4 and the open ends of the resonance lines 2a and 2b. This line switching movable part 3 is displaced in the direction of the arrow shown in the figure, and is in electrical contact with the open end of one of the resonance lines 2a or 2b. A circuit such as an oscillation circuit or a variable capacitance diode is formed at the end of the microstrip line 4 using a chip component 5 or the like.
[0017]
Next, a more specific configuration example of the line switching movable portion will be described with reference to FIGS.
In FIG. 3, reference numeral 7 denotes a magnetic piece, which is made of a ferromagnetic material such as Fe or Ni alloy and a metal material having high conductivity. An electromagnet 6 attracts the magnetic piece 7. When the coil of the electromagnet 6 is energized, the end of the magnetic piece 7 is brought into contact with the resonance line 2b side. When the coil is not energized, its end is in contact with the resonance line 2a due to the elasticity of the magnetic piece 7. Thereby, the resonance line is switched by driving the electromagnet 6.
[0018]
In FIG. 4, the line switching movable portion 3 is a metal plate having a spring property, and 8 is a piezoelectric actuator. Normally, as shown in the figure, it is in contact with the resonance line 2a side, but by applying a drive voltage to the piezoelectric actuator 8, the piezoelectric actuator 8 pushes the movable part 3 toward the resonance line 2b side.
[0019]
In FIG. 5, 9 is a bimorph piezoelectric actuator, and an electrode 10 continuous with the microstrip line 4 is formed in the vicinity of the end of the piezoelectric actuator. In a state where no driving voltage is applied to the piezoelectric actuator 9, the electrode 10 is in contact with the end of the resonance line 2a. When a control voltage is applied to the piezoelectric actuator 9, the electrode 10 is displaced toward the resonance line 2b and becomes electrically conductive.
[0020]
In any of the examples shown in FIGS. 2 to 5, the line switching movable part is exaggeratedly drawn so as to be largely displaced, but the actual displacement amount of the line switching movable part may be very small. .
[0021]
Next, an example of an oscillator having another circuit configuration will be described with reference to FIG.
In the example shown in FIG. 1, one end of each of the two resonance lines is grounded, and the oscillation circuit is selectively connected to the other end. However, in the example shown in FIG. 6, two resonance lines 2a, One end of 2b is connected in common and connected to the oscillation circuit, and the other end is selectively grounded via the line switching movable part 3. Thereby, it is possible to oscillate at the resonance frequency of the resonance line on the side grounded by switching of the line switching movable portion 3. Although the resonance line on the side not grounded has a resonator structure with one end open, the resonance frequency is far from a predetermined frequency band, and has no substantial effect.
[0022]
Next, a configuration example of the filter will be described with reference to FIG.
FIG. 7 is a circuit diagram of the filter. One end of each of the two resonance lines 2a and 2b is grounded, and the other end is connected to a predetermined point on the transmission line via the line switching movable portion 3. Therefore, when the line switching movable part 3 selects the resonance line 2a side, it acts as a trap filter that blocks the vicinity of the resonance frequency of the resonance line 2a, and the line switching movable part 3 selects the resonance line 2b side. When this occurs, it acts as a trap filter that blocks the vicinity of the resonant frequency of the resonant line 2b.
[0023]
In the example shown in FIG. 7, only a single resonant line is selectively connected to the transmission line. Similarly, by connecting a plurality of resonant lines to the transmission line, a predetermined bandwidth can be obtained. A band-rejecting filter that attenuates can be configured.
[0024]
Next, a configuration example of the duplexer and the communication device will be described with reference to FIG.
Here, the band rejection filter is used as the reception filter and the transmission filter. Then, the stop band of the transmission filter is matched with the reception signal band, and the stop band of the reception filter is matched with the transmission signal band. A communication device is configured by connecting a receiving circuit and a transmitting circuit to such a duplexer and connecting an antenna.
[0025]
【The invention's effect】
According to the first aspect of the invention, the line can be conducted with a resistance lower than the equivalent series resistance of the diode by selectively conducting the two resonance lines with the line switching movable portion. The decrease in Q is suppressed.
[0026]
According to the second aspect of the present invention, the line switching movable part can be easily configured on the substrate without increasing the size of the whole.
[0027]
According to the third aspect of the present invention, a large movable amount of the line switching movable portion can be ensured, and the selective switching between the two resonance lines can be reliably performed.
[0028]
According to the fourth aspect of the present invention, an oscillator in which the variable range of the oscillation frequency is widened and the deterioration of the C / N ratio is prevented can be obtained.
[0029]
According to the fifth and sixth aspects of the invention, it is possible to switch the frequency characteristics and reduce the loss.
[0030]
According to the seventh aspect of the invention, since the loss generated in the frequency switching unit is small, high efficiency can be achieved.
[Brief description of the drawings]
FIG. 1 is a circuit diagram showing a configuration of an oscillator according to an embodiment. FIG. 2 is a partial perspective view showing a configuration of the oscillator. FIG. 3 is a partial perspective view showing a configuration of an oscillator according to a second embodiment. FIG. 5 is a partial perspective view showing the configuration of the oscillator according to the third embodiment. FIG. 5 is a partial perspective view showing the configuration of the oscillator according to the fourth embodiment. FIG. 6 shows the configuration of the oscillator according to the fifth embodiment. FIG. 7 is a diagram showing a configuration of a filter according to a sixth embodiment. FIG. 8 is a diagram showing a configuration of a duplexer and a communication device according to the seventh embodiment. FIG. 9 is a diagram showing a configuration of a conventional oscillator. Circuit diagram shown [Explanation of symbols]
1-dielectric plates 2a, 2b-resonance line 3-line switching movable part 4-microstrip line 5-chip component 6-electromagnet 7-magnetic body piece 8, 9-piezoelectric actuator 10-electrode

Claims (7)

By strip line or microstrip line on a dielectric plate, a different Do that two resonant lines of the resonant frequency provided, a resonator having a line switching movable portion for selectively turned to the two resonant lines,
The dielectric plate has an inner surface on which open ends of the two resonance lines are formed,
The resonator, wherein the line switching movable portion is disposed between the open ends of the two resonance lines in a space surrounded by the inner surface in the dielectric plate.   The resonator according to claim 1, wherein a drive source of the movable part for line switching is a piezoelectric element. The resonator according to claim 1, wherein a drive source of the movable section for line switching is configured by a coil and a movable magnetic piece.   An oscillator comprising a negative resistance circuit connected to the resonator according to claim 1. A transmission line connected between the input terminal and the output terminal, and the resonator according to claim 1, 2, or 3, wherein the line switching movable portion of the resonator is connected to the transmission line. A filter in which an end of the resonator opposite to the open ends of the two resonance lines is grounded. Receiving one filter, the other as a transmission filter, 2 Kumisonae a filter according to claim 5, the stop band of the reception filter is a transmission signal band, stop band of the transmit filter received signal band der Lud Duplexer.   A communication apparatus comprising the resonator according to claim 1, the oscillator according to claim 4, the filter according to claim 5, or the duplexer according to claim 6.

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