JP2985223B2 - Method and apparatus for measuring resonance frequency and load Q of resonator - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and a device for measuring a resonance frequency and a load Q of a resonator such as a dielectric resonator.

[Prior Art] FIG. 5 shows a resonance frequency and a load Q of a dielectric resonator 111.
2 shows a conventional measurement method.

In FIG. 5, a cylindrical dielectric resonator 111 is placed in the center of the shield case 110, and one-turn coils 121 and 122 are provided on the inner surfaces of the shield cases 110 on both sides of the dielectric resonator 111, respectively. Is provided. A frequency sweep signal including the resonance frequency of the dielectric resonator 111 is input from the sweep signal generator 101 to the coil 121, while the frequency spectrum characteristic of the signal output from the coil 122 is measured by the spectrum analyzer 102.

It is located on both sides of the resonance frequency f ₀ in the frequency spectrum characteristic of the measured signal and 3d from the maximum level point.
Frequency at the point reduced by B (hereinafter referred to as the 3dB reduction point)
f ₁ and f ₂ (f ₁ <f ₂ ) are measured, and the above measured frequencies f ₁ and f ₂
Into the following equation to calculate and obtain the resonance frequency f ₀ , Further, the load Q (Q _L ) of the dielectric resonator 111 is calculated by substituting the calculated resonance frequency f ₀ and the measured frequencies f ₁ and f ₂ into the following equation.

In addition, the resonance frequency f ₀ and the load Q of the dielectric resonator 111 can be similarly measured using a network analyzer instead of the sweep signal generator 101 and the spectrum analyzer 102.

[Problems to be Solved by the Invention] However, the conventional method has a problem that an expensive measuring instrument such as the spectrum analyzer 102 or the network analyzer is required.

An object of the present invention is to solve the above problems and to provide a measuring method and a measuring device that can measure the resonance frequency and the load Q of a resonator with a measuring device that is inexpensive compared to the related art.

[Means for Solving the Problems] A method for measuring a resonance frequency of a resonator according to claim 1 of the present invention measures two oscillation loop circuits having amplification means for amplifying an oscillation signal and having mutually different electrical lengths. The resonators are alternately switched and electrically connected to each other to oscillate the resonators in a predetermined fundamental mode, and the oscillation frequencies of the respective oscillation signals generated in the two oscillation loop circuits are measured. Calculate each transmission phase of each oscillation loop circuit excluding the resonator based on each measured oscillation frequency, and calculate each transmission phase of the resonator and each oscillation frequency calculated based on each transmission phase. The resonance frequency of the resonator is calculated and measured based on the calculated value.

According to a second aspect of the present invention, there is provided a method of measuring a load Q of a resonator, comprising an amplifying means for amplifying an oscillation signal, and alternately connecting two oscillation loop circuits having different electrical lengths to the resonator to be measured. Switch and electrically connect, each of the resonators oscillates in a predetermined basic mode, and measures the oscillation frequency of each oscillation signal generated in each of the two oscillation loop circuits. Based on each transmission phase of each of the oscillation loop circuits except for the resonator based on the transmission phase, the load of the resonator is calculated based on each transmission phase of the resonator calculated based on each transmission phase and each oscillation frequency. It is characterized by calculating and measuring Q.

Furthermore, the measuring device for measuring the resonance frequency of the resonator according to the third aspect of the present invention is provided with an amplifying means for amplifying an oscillation signal, comprising two oscillation loop circuits having different electric lengths, and measuring the two oscillation loop circuits. Switching means for alternately switching and electrically connecting to the resonators to be oscillated, and oscillating the resonators in a predetermined fundamental mode, and measuring the oscillation frequency of each oscillation signal generated in each of the two oscillation loop circuits. Frequency measuring means, calculating each transmission phase of each oscillation loop circuit excluding the resonator based on each oscillation frequency measured by the frequency measurement means, and calculating the resonator based on each transmission phase. Calculating means for calculating a resonance frequency of the resonator based on each transmission phase and each oscillation frequency.

Still further, according to a fourth aspect of the present invention, there is provided an apparatus for measuring a load Q of a resonator, comprising: amplification means for amplifying an oscillation signal; two oscillation loop circuits having different electrical lengths; Switching means for alternately switching and electrically connecting the resonators to be measured to oscillate the resonators in a predetermined fundamental mode, and measuring the oscillation frequency of each oscillation signal generated in each of the two oscillation loop circuits Frequency measuring means to calculate each transmission phase of each oscillation loop circuit excluding the resonator based on each oscillation frequency measured by the frequency measurement means, and calculate the resonance phase calculated based on each transmission phase. Calculating means for calculating a load Q of the resonator based on each transmission phase of the resonator and each of the oscillation frequencies.

[Operation] With the configuration described above, two oscillation loop circuits having amplification means for amplifying an oscillation signal and having mutually different electrical lengths are alternately switched to a resonator to be measured and electrically connected, Each of the resonators is oscillated in a predetermined basic mode, and the oscillation frequency of each oscillation signal generated in each of the two oscillation loop circuits is measured, thereby eliminating the resonators based on the measured oscillation frequencies. Calculating each transmission phase of each oscillation loop circuit, and calculating a resonance frequency and a load Q of the resonator based on each transmission phase of the resonator calculated based on each transmission phase and each oscillation frequency. Can be measured.

According to the present invention, two oscillation loops having different electrical lengths from each other and electrically connected to the resonator to be measured are not measured based on the frequency spectrum characteristic of the resonator measured by the frequency sweep signal as in the conventional example, but are measured. The oscillation frequency of each oscillation signal generated in the circuit is measured, each transmission phase of each oscillation loop circuit excluding the resonator is calculated based on each measured oscillation frequency, and based on each transmission phase. Since the resonance frequency and the load Q of the resonator are calculated and measured based on the calculated transmission phases of the resonator and the oscillation frequencies, the cost is automatically measured using an inexpensive device as compared with the conventional example. The resonance frequency and the load Q of the resonator can be measured.

[Embodiment] Hereinafter, with reference to the drawings, an apparatus for measuring a resonance frequency and a load Q of a dielectric resonator according to an embodiment of the invention will be described.
The description will be made in the following order.

(1) Configuration of measurement device for resonance frequency and load Q of dielectric resonator (2) Measurement principle of resonance frequency and load Q of dielectric resonator (3) Measurement flow of measurement device (4) Other embodiments In the measurement apparatus of the embodiment, in the two oscillation loop circuits configured by switching the switches SW2 and SW3 in conjunction with each other and having different electric lengths, the dielectric resonator 11 respectively oscillates differently in the _TE01δ mode which is the fundamental mode. frequency
Oscillation is performed at f ₁ and f ₂ , and respective oscillation frequencies f ₁ and f ₂ are measured. Based on the _two measured oscillation frequencies f ₁ and f ₂ , the resonance frequency f ₀ of the dielectric resonator 11 and the load Q Is calculated.

(1) Configuration of Measurement Apparatus for Resonant Frequency and Load Q of Dielectric Resonator FIG. 1 is a block diagram of a measurement apparatus for resonance frequency and load Q of dielectric resonator 11 according to one embodiment of the present invention. FIG. 2 is a longitudinal sectional view of the dielectric resonator 11 of FIG. 1 and the shield case 10 accommodating the same.

This measuring device includes a filtering operation mode in which the dielectric resonator 11 operates as a band-pass filter,
It has two operation modes of 11 measurement modes for measuring the resonance frequency f ₀ and the load Q.

As shown in FIGS. 1 and 2, a cylindrical dielectric resonator 11 to be measured has the same linear expansion coefficient as the dielectric resonator 11 at a central portion in a cylindrical shield case 10. It is placed on a support 14. This dielectric resonator 11
For example, it is a ceramic dielectric resonator in which an oxide such as MgO, BaO, or ZrO ₂ is mixed with TiO ₂ as a main component, and the dielectric resonator 11 of the present embodiment has about a TE _01δ mode as a fundamental mode. having a resonant frequency f ₀ of 800MHz. Further, inside the cylinder of the dielectric resonator 11, a cylindrical dielectric 12 is provided.
Is supported by the shaft 15 and provided.
The move in the arrow A ₁ direction, the dielectric 12 by moving in a gradient of the electric field of the dielectric resonator 11, it is possible to finely adjust the resonant frequency f ₀ of the dielectric resonator 11 .

The shield case 10 is configured by baking silver electrodes on the outer surface of a cylindrical housing made of ceramics having the same linear expansion coefficient as the dielectric resonator 11 for electromagnetic shielding. As shown in FIG. 2, the inner surface of the shield case 10 is coupled to the magnetic field H of the dielectric resonator 11 at four positions separated from each other by 90 degrees with respect to the center of the cylinder. Thus, for example, one-turn coils 21, 22, 23, 24 for inputting / outputting signals are provided. Here, the coil used in the filtering operation mode
21 and 22 are provided to face each other with the dielectric resonator 11 therebetween, and coils 23 and 24 used in the measurement operation mode are provided to face each other with the dielectric resonator 11 therebetween.

In the filtering operation mode, the switch SW1 is turned on and the switch SW4 is turned off. After a signal of about 800 MHz band output from the high-frequency signal generator 1 is input to the coil 21 via the switch SW1, the input is performed. The resulting signal is filtered by the dielectric resonator 11. The filtered signal is coil 22
Is output to the load 2.

On the other hand, in the oscillation operation mode, the switch SW1 is turned off and the switch SW4 is turned on. At this time, in the selected one of the two oscillation loop circuits connected between the coils 23 and 24 and configured to satisfy the oscillation conditions described later in detail, the dielectric resonator
An oscillation signal oscillating at TE _01δ , which is the eleven basic mode, is generated.

When the switches SW2 and SW3 are switched to the a side in conjunction with each other, the first oscillation loop circuit is connected between the coils 23 and 24, and the oscillation signal output from the coil 24 is the switch SW2
A, a predetermined characteristic impedance Z ₀ and a predetermined electric length λ
microstrip line 31 having g ₁ and switch SW
The signal is input to the input terminal of the amplifier 33 having the amplification degree A through the a side 3. On the other hand, when the switches SW2 and SW3 are switched to the b side in conjunction with each other, the second oscillation loop circuit is connected between the coils 23 and 24, and the oscillation signal output from the coil 24 becomes the b side of the switch SW2. predetermined characteristic impedance Z ₀ and the microstrip line 32 and microstrip line 32 having a different electrical length lambda] g _2, and via the b-side of the switch SW3 is inputted to the input terminal of the amplifier 33.

The oscillation signal output from the output terminal of the amplifier 33 is output to the coil 23 via the transmission line connected between the ports 34a and 34b of the directional coupler 34 and the switch SW4. The switches SW1, SW2, SW3, and SW4 described above are described in detail later,
Switching is controlled by a microprocessor unit (hereinafter, referred to as an MPU) 40 which is a control device of the measuring device.

A port 34d for detecting an oscillation signal which is a traveling wave passing through a transmission line between the ports 34a and 34b of the directional coupler 34
Is connected to a frequency counter 35, and a port 34c for detecting a reflected wave passing through the transmission line is terminated by a load 34e having a predetermined characteristic impedance. This frequency counter 35 measures the frequency of the oscillation signal detected at the port 34d, and outputs data fm of the measured frequency.
Output to MPU40.

The MPU 40 controls the measuring device to measure the resonance frequency f ₀ and the load Q of the dielectric resonator 11 (not shown),
A control program for controlling the measuring device and data necessary for executing the control program are stored.
ROM (not shown), RAM (not shown) used as a working memory of the CPU, and switches SW1, SW2, S
It includes an input / output port circuit (not shown) connected to W3, SW4, frequency counter 35, and CRT display 41 and operating as an interface circuit. The MPU 40 controls switching of the switches SW1, SW2, SW3, and SW4, and receives data fm of the measured frequency from the frequency counter 35, as described later in detail. calculate the resonant frequency f ₀ and the load Q (Q _L) of displaying these data on the CRT display 41.

(2) Principle of Measuring Resonant Frequency and Load Q of Dielectric Resonator The oscillation conditions in the first and second oscillation loop circuits shown in FIG. 1 are expressed by the following equations.

_{Re (A · β 1) =} 1 ... (2a) Im (A · β 1) = 0 ... (2b) Re (A · β 2) = 1 ... (3a) Im (A · β 2) = 0 ... ( here 3b), a is the amplification factor of the amplifier 33, beta ₁ is a feedback amount in the first oscillation loop circuit, beta ₂ is a feedback amount in the second oscillation loop circuit. As described above, the electrical lengths λg ₁ and λg _{2 of the} microstrip line 31 and the microstrip line 32 are different from each other, and the feedback amounts β ₁ and β _{2 in} the first and second oscillation loop circuits are different from each other. From the above equations (2b) and (3b), it can be seen that oscillation signals having different oscillation frequencies f ₁ and f ₂ are generated in the first and second oscillation loop circuits, respectively.

In the first oscillation loop circuit, when the dielectric resonator 11 dielectric resonator 11 apparatus and ₁ the transmission phase Θ of the line other than at any frequency fa in proximity to the resonance frequency f ₀ of,
Transmission phase theta ₁ of the dielectric resonator 11 is expressed by the following equation.

Here, n is an integer.

On the other hand, in the second oscillation loop circuit, the dielectric resonator
When the 11 any device other than the dielectric resonator 11 at a frequency fa and the line of transmission phase close to the resonance frequency f ₀ and theta _2, transmission phase theta ₂ of the dielectric resonator 11 is represented by the following formula .

Here, n is an integer, and the transmission phases Θ1 and Θ2 are device constants that can be measured in advance. Therefore, the transmission phases θ ₁ and θ ₂ of the dielectric resonator 11 in each oscillation loop circuit can be obtained by measuring the oscillation frequencies f ₁ and f ₂ in each oscillation loop circuit.

When the resonance frequency of the resonator and f _0, in general, the following relationship is established between the transmission phase θ of the resonator and its load Q (Q _L).

Therefore, when the first and second oscillation loop circuits are applied to the above equation (6), the following equation is obtained.

The following equation is obtained by eliminating the load Q (Q _L ) using equations (7) and (8) and solving for the resonance frequency f ₀ .

Further, the following equation is obtained by substituting the above equation (9) into the equation (7).

Here, F ₁ = f ₁ tan θ ₁ −f ₂ tan θ ₂ (11a) F ₂ = f ₂ tan θ ₁ −f ₁ tan θ ₂ (11b)

Accordingly, the oscillation frequency f ₁ of the oscillation signal generated in the first oscillation loop circuit is measured and, after measuring the oscillation frequency f ₂ of the oscillation signal generated in second oscillation loop circuit, which is the measured oscillation By substituting the frequencies f ₁ and f ₂ into the above equations (4) and (5), the transmission phases θ ₁ and θ ₂ of the dielectric resonator 11 can be calculated.
Further, the calculated transmission phases θ ₁ , θ ₂ and the measured oscillation frequencies f ₁ , f ₂ are expressed by the above equations (9), (10), (11).
a) By substituting into equations (11b),
The resonance frequency f ₀ and the load Q (Q _L ) of the dielectric resonator 11 can be calculated and measured.

(3) Measurement Flow of Measurement Apparatus FIG. 3 is a flowchart showing a measurement flow in the measurement operation mode of the measurement apparatus of FIG. 1. The measurement flow of the measurement apparatus will be described with reference to FIG.

First, in step # 1, the switch SW1 is turned off, the switch SW4 is turned on, and the measuring apparatus is set to the measurement operation mode. In step # 2, the switches SW2 and SW3 are switched to the a side in conjunction with each other. Then, the first oscillation loop circuit is connected between the coils 23 and 24.

Then, at step # 3, the oscillation frequency f ₁ of the oscillation signal generated in the first oscillation loop circuit is measured by the frequency counter 35, and stores the data fm in the RAM in the MPU40 the oscillation frequency f _1. Further, at step # 4, the (4) by substituting the oscillation frequency f ₁ which is the measurement to calculate the transmission phase theta ₁ of the dielectric resonator 11 in formula, and stores the calculated results into the RAM.

Next, in step # 5, the switches SW2 and SW3 are interlocked and switched to the b side to connect the second oscillation loop circuit between the coils 23 and 24. Then, in step # 6, the second oscillation loop circuit the oscillation frequency f ₂ of the oscillator signal generated measured by the frequency counter 35, and stores the oscillation frequency f ₂ of the data fm in the RAM in the MPU 40. Further, at step # 7, the (5) by substituting the measured oscillation frequency f ₂ calculate the transmission phase theta ₂ of the dielectric resonator 11 in formula, and stores the calculated results into the RAM.

Next, in step # 8, the calculated transmission phases θ ₁ and θ ₂ and the measured oscillation frequencies f ₁ and f ₂ are compared with the above equations (9), (10), (11a) and (11b). By substituting into the equation, the resonance frequency of the dielectric resonator 11
f ₀ and to calculate the load Q (Q _L), after displaying the calculated results on the CRT display 41, in step # 9, the on-off Toshikatsu switch SW1 switches SW4, filtering the measuring device The operation mode is set, and the measurement process ends.

(4) Other Embodiments In the above embodiments, the first and second oscillation loop circuits are formed by switching the two microstrip lines 31 and 32 by the switches SW2 and SW3. Without limitation, the switches 31 and 32 are not used, and two signal input / output coils configured in the same manner as the coils 23 and 24 are provided to form two oscillation loop circuits independent of each other and having different electrical lengths. You may. In this case, when in the filtering operation mode, both of the two oscillation loop circuits are turned off, and in the measurement operation mode, one oscillation loop circuit is turned on and the other oscillation loop circuits are turned off. Then, with one oscillation loop circuit turned off and the other oscillation loop circuit turned on, the measurement operation may be performed in the same manner as in the above-described embodiment.

In the above embodiment, the two microstrip lines 31 and 32 are switched by the switches SW2 and SW3 to configure the first and second oscillation loop circuits. However, the present invention is not limited to this, and FIG. As shown, microstrip line
31 and 32 and switches SW2 and SW3, the transmission phase θs
A phase shifter 50 configurable by 0 may be connected between the coil 24 and the amplifier 33. In this case, in order to form two oscillation loop circuits, the MPU 40 sets two different and predetermined transmission phases θs ₁ and θs ₂ that can oscillate in the oscillation loop circuit. At this time, similarly to the above-described embodiment, the transmission phase Θ ₁ of the devices other than the dielectric resonator 11 in the first and second oscillation loop circuits and the transmission phase Θ ₁ ,
Θ ₂ can be measured in advance.

In the above embodiment, the microstrip lines 31, 3
2, the present invention is not limited to this, and transmission lines such as coplanar lines and slot lines having different electrical lengths may be used.

In the above embodiments, the measuring method and the measuring apparatus for measuring the resonance frequency and the load Q of the dielectric resonator 11 have been described. However, the present invention is not limited to this, and the present invention is not limited to this. Can be applied to other types of resonators.

[Effects of the Invention] As described above in detail, according to the present invention, the resonator to be measured is electrically measured instead of being measured based on the frequency spectrum characteristic of the resonator measured by the frequency sweep signal as in the conventional example. The oscillation frequency of each oscillation signal generated in each of the two oscillation loop circuits having different electrical lengths is measured, and based on each of the measured oscillation frequencies, each of the oscillation loop circuits excluding the resonator is measured. A transmission phase is calculated, and a resonance frequency and a load Q of the resonator are calculated and measured based on each transmission phase and each oscillation frequency of the resonator calculated based on each transmission phase. There is an advantage that the resonance frequency and the load Q of the resonator can be automatically measured by using an inexpensive device as compared with the first embodiment.

[Brief description of the drawings]

FIG. 1 is a block diagram of an apparatus for measuring the resonance frequency and load Q of a dielectric resonator according to one embodiment of the present invention. FIG. 2 is a longitudinal section of the dielectric resonator of FIG. 1 and a shield case accommodating the same. FIG. 3 is a flowchart showing a measurement flow in a measurement operation mode of the measurement apparatus of FIG. 1, FIG. 4 is a block diagram showing a modification of the measurement apparatus of FIG. 1, and FIG. 5 is a dielectric resonator FIG. 6 is a block diagram showing a conventional method for measuring the resonance frequency and load Q of the conventional method. 11: Dielectric resonator, 23, 24: Coil, 31, 32: Microstrip line, 33: Amplifier, 34: Directional coupler, 35: Frequency counter, 40: Microprocessor unit ( MPU), 50 ... phase shifter, SW2, SW3 ... switch.

Claims (4)

(57) [Claims] 1. An oscillator for amplifying an oscillation signal, wherein two oscillation loop circuits having different electric lengths are alternately switched and electrically connected to a resonator to be measured, and each of the resonators is connected to a predetermined resonator. Oscillate in the basic mode, measure the oscillation frequency of each oscillation signal generated in each of the two oscillation loop circuits, and determine the transmission phase of each oscillation loop circuit excluding the resonator based on the measured oscillation frequency. Calculating the resonance frequency of the resonator based on each transmission phase and each oscillation frequency of the resonator calculated based on each transmission phase, and measuring the resonance frequency of the resonator. How to measure frequency. 2. An oscillation circuit comprising amplification means for amplifying an oscillation signal, wherein two oscillation loop circuits having different electric lengths are alternately switched and electrically connected to a resonator to be measured, and each of the resonators is connected to a predetermined resonator. Oscillate in the basic mode, measure the oscillation frequency of each oscillation signal generated in each of the two oscillation loop circuits, and determine the transmission phase of each oscillation loop circuit excluding the resonator based on the measured oscillation frequency. And calculating and measuring a load Q of the resonator based on each transmission phase and each oscillation frequency of the resonator calculated based on each transmission phase. How to measure Q. 3. An oscillation circuit having amplification means for amplifying an oscillation signal, two oscillation loop circuits having different electric lengths from each other, and the two oscillation loop circuits being alternately switched to and electrically connected to a resonator to be measured. Switching means for causing the resonator to oscillate in a predetermined fundamental mode; frequency measuring means for measuring the oscillation frequency of each oscillation signal generated in each of the two oscillation loop circuits; and each oscillation frequency measured by the frequency measuring means Based on the transmission phase of each of the oscillation loop circuit except the resonator, based on the transmission phase of the resonator calculated based on the transmission phase and the oscillation frequency of the resonator based on each oscillation frequency A calculating device for calculating a resonance frequency, the device for measuring the resonance frequency of a resonator. 4. An oscillation circuit comprising amplification means for amplifying an oscillation signal, two oscillation loop circuits having different electric lengths from each other, and said two oscillation loop circuits are alternately switched to and electrically connected to a resonator to be measured. Switching means for causing the resonator to oscillate in a predetermined fundamental mode; frequency measuring means for measuring the oscillation frequency of each oscillation signal generated in each of the two oscillation loop circuits; and each oscillation frequency measured by the frequency measuring means Based on the transmission phase of each of the oscillation loop circuit except the resonator, based on the transmission phase of the resonator calculated based on the transmission phase and the oscillation frequency of the resonator based on each oscillation frequency An apparatus for measuring a load Q of a resonator, comprising: calculation means for calculating a load Q.