JPH11234007A - High-frequency module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-frequency module which suppresses decrease in QL of a dielectric resonator part provided to a dielectric plate and capable of having its impedance easily matched with an FET, etc. SOLUTION: A conductive film 15 is formed on both the main surfaces of the dielectric plate 1 except some parts to form dielectric resonator parts at the parts 17 and 19, where the conductor film 15 is not formed, a dielectric sheet 2 where lines 6 and 7 are formed is superposed to couple the dielectric resonator parts and lines with each other, and the lines 6 and 7 coupled with the dielectric resonator parts are made narrow in width to suppress the decrease in the QL the resonator parts. Furthermore, the impedance of the part connected to the FET is increased to suppress the reflections due to mismatching.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-frequency module such as a resonator, a filter, and an oscillator used in a microwave band or a millimeter wave band.

[0002]

2. Description of the Related Art With the recent increase in demand for mobile communication systems and the amount of transmitted information, the communication band has been expanded to the millimeter wave band. When a dielectric filter or a voltage controlled oscillator (hereinafter, referred to as a VCO) is formed using a TE01δ mode dielectric resonator in such a high frequency band, the resonance frequency of a general TE01δ mode dielectric resonator is a column. Since the shape is determined by the outer dimensions of the dielectric and the coupling with the microstrip line is determined by the distance between them, high dimensional accuracy and positioning accuracy are required.

Accordingly, the applicant of the present application has filed Japanese Patent Application No. 7-6262.
No. 5 proposes a dielectric resonator and a dielectric filter which solve these problems and have excellent processing accuracy.

In the dielectric resonator and the dielectric filter according to the above-mentioned application, a part of the dielectric plate is used as a dielectric resonator by forming electrodes on both main surfaces of the dielectric plate. In such a dielectric resonator, since the electrode formed on the dielectric plate can be used as a ground electrode, a microstrip line is formed on another dielectric sheet or the like and laminated on the dielectric plate. Thereby, a high-frequency module such as a VCO including the dielectric resonator and the electronic component can be configured.

A dielectric resonator device in which a part of a dielectric plate is used as a dielectric resonator, a sheet on which a line is formed is superposed on the dielectric plate, and the dielectric resonator and the line are coupled, and a high-frequency A module is proposed in Japanese Patent Application No. 8-294087.

FIG. 7 is a perspective view showing an example of the configuration. In FIG. 1, reference numeral 1 denotes a dielectric plate, and a conductive film is formed on both main surfaces of the dielectric plate except for a part thereof, thereby forming a TE010-mode dielectric resonator unit. Reference numeral 2 denotes a dielectric or insulating sheet, on which the lines 24 and 25 are formed. With the sheet 2 stacked on the dielectric plate 1, the lines 24 and 25 are magnetically coupled to the dielectric resonator.

[0007]

In the conventional high-frequency module shown in FIG. 7, the characteristic impedance (hereinafter simply referred to as "impedance") of each part of the line is designed.
0Ω, and the impedance of the line coupled to the dielectric resonator unit is also set to 50Ω.

However, in such a high-frequency module, since a line, which is a conductor, is inserted into the resonance space of the dielectric resonator section due to its structure, conductor loss occurs at that portion, and the resonator is damaged. , The load Q (Q _L ) decreases. In particular, in the 50Ω line, for the line width is thick, increasing the amount of insertion of the resonant space, so that the Q _L is significantly reduced.

Further, since the input impedance of the FET connected to the end of the line is generally higher than 50Ω, it is necessary to provide an impedance matching circuit.

An object of the present invention is to solve the degradation problems of Q _L of the dielectric resonators constituting the dielectric plate, also FET
It is an object of the present invention to provide a high-frequency module capable of easily achieving impedance matching with the above.

[0011]

According to the present invention, a conductive film is formed on both main surfaces of a dielectric plate except for a part thereof, and a portion where the conductive film is not formed is defined as a dielectric resonator portion. A high-frequency module in which a sheet on which a line partially coupled to the dielectric resonator unit is formed is superposed on the dielectric plate, as described in claim 1, coupled to at least the dielectric resonator unit of the line. Make the line width of the part to be narrower than other parts. This reduces the conductor area inserted into the resonance space,
As a result Q _L is increased. Further, when a high input impedance FET such as an FET is connected to one end of the line, the line width is reduced to the connection portion of the FET and the impedance of the line is increased so that impedance matching with the FET can be easily achieved. Will be able to

According to a second aspect of the present invention, an impedance matching section is provided between at least a portion of the line coupled to the dielectric resonator portion and another portion. This prevents impedance mismatch between the narrow portion of the line coupled to the dielectric resonator portion and the other portions, thereby preventing the occurrence of reflection loss and unstable operation due to reflection.

According to a third aspect of the present invention, another dielectric plate sandwiching the sheet is provided between the line portion and the dielectric plate. Thus, the other dielectric plate is close to the line provided on the sheet, and a microstrip line is formed at that portion, so that the line width can be reduced while keeping the characteristic impedance of the line constant. Therefore, it is not necessary to provide a special impedance matching unit.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of a bandpass filter according to a first embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is an exploded perspective view of the main part. In FIG. 1, reference numeral 1 denotes a dielectric plate, on which conductive films are formed on upper and lower surfaces. However, the conductor film 15 is provided on the upper surface in the figure so that the conductor non-formed portions 17 and 19 are formed. On the lower surface of the dielectric plate 1 in the drawing, a conductor film having a conductor non-formation portion of the same shape is formed at a portion facing the conductor non-formation portions 17 and 19.
With this structure, two TE010-mode dielectric resonator units are formed on the dielectric plate sandwiched between the non-conductor-formed portions. In FIG. 1, reference numeral 2 denotes a dielectric sheet made of PTFE or the like, and lines 6 and 7 are formed on the upper surface in the figure. The roots 6a, 7a of these lines 6, 7 respectively
Is a transmission line having a relatively large line width, and the protruding portions 6b and 7b are used as probes having a small line width.
When the dielectric sheet 2 is placed on the dielectric plate 1 on which the conductive film is formed, the probes 6b and 7b are coupled to the two dielectric resonator sections. Further, by sandwiching these dielectric plates and dielectric sheets between the conductor plates 4 and 5, the dielectric resonator unit and the line are arranged between the two parallel conductor plates.

FIG. 2 is a diagram showing a state in which a dielectric sheet is overlaid on the dielectric plate shown in FIG. 1, (A) is a plan view,
(B) is the center sectional view. Thus, the dielectric plate 1
Conductive film 1 provided with non-conductive portions 17 and 19 on the upper surface of
5 is formed on the lower surface of the dielectric plate 1,
By forming the conductor film 16 provided with 20, 2
Two TE010-mode dielectric resonator sections are formed in a portion sandwiched between the non-conductor-formed portions. The dashed line in (B) of the figure shows the magnetic field distribution of that mode, and two adjacent dielectric resonators are magnetically coupled. Each resonator section is magnetically coupled to the probes 6b and 7b. As a result, a filter having a band-pass characteristic composed of two stages of resonators is formed between the transmission lines 6a-7a.

Here, the transmission lines 6a and 7a are set to have an impedance of 50Ω in accordance with a circuit having an input / output impedance of 50Ω or a line having an impedance of 50Ω. Since the line widths of the probes 6b and 7b are formed thinner than 6a and 7a, the impedance is higher than 50Ω. By narrowing the line width of the probe to be inserted in this manner into the resonant space, the conductor loss is reduced, decrease in Q _L of the dielectric resonator portion can be suppressed.

Next, the structure of a dielectric filter according to a second embodiment will be described with reference to FIGS.

FIG. 3 is an exploded perspective view thereof. In the figure, reference numeral 1 denotes a dielectric plate, on which a conductor film 15 is provided so that circular conductor non-formed portions 17 and 19 are formed on the upper surface in the figure. On the lower surface of the dielectric plate 1 in the drawing, a conductor film having a conductor non-formation portion of the same shape is formed at a portion facing the conductor non-formation portions 17 and 19. With this structure, two T
An E010 mode dielectric resonator section is formed. FIG.
In the figure, 2 is a dielectric sheet made of PTFE or the like, and forms a line 6 on the upper surface in the figure. By overlapping the dielectric sheet 2 on the dielectric plate 1 on which the conductive film is formed, a part of the line 6 is coupled to two dielectric resonator portions. Further, by sandwiching the dielectric plate and the dielectric sheet between the conductive plates 4 and 5, the dielectric resonator unit and the line are arranged between the two parallel conductive plates.

FIG. 4 is a plan view showing a state in which the dielectric sheet 2 is laminated on the dielectric plate 1 shown in FIG. As described above, both end portions 6a of the line 6 are transmission lines having a relatively large line width, and intermediate portions 6b are probes having a small line width.
Further, an impedance matching section 6c is formed at an intermediate portion between the transmission line and the probe. Here, the impedance of the transmission line 6a is Za, and the impedance of the probe 6b is Z
If b, the impedance Zc of the impedance matching unit 6c is a line width satisfying the relationship of Zc = √ (Za · Zb), and the line length is λg / 4 (λg is a transmission line wavelength). The probe 6b includes two TEs provided on the dielectric plate 1.
Magnetic field coupling is performed with respect to the 010 mode dielectric resonator. The interval between the coupling positions is an odd multiple of λg / 4. As a result, a dielectric filter having band rejection characteristics in which two resonators are coupled to predetermined positions of the transmission lines 6a, 6a is obtained.

Next, FIG. 5 is an exploded perspective view showing the structure of the main part of the VCO according to the third embodiment. In the figure, 21 is a VCO module and 50 is a ceramic package. One TE010-mode dielectric resonator unit R is formed on the dielectric plate 1 of the VCO module 21 in the same manner as that shown in FIG. An FET 28 and a varactor diode 29 are mounted on the upper surface of the dielectric plate 1. The transmission line 24a, the probe 24b, the impedance matching unit 24c are provided on the upper surface of the dielectric sheet 2.
A transmission line 25a, a probe 25b,
The sub-line including the impedance matching section 25c is formed so as to overlap the dielectric resonator section R. Transmission line 24
One end of a is connected to a ground electrode 27 via a resistive film 26, and the other end of the probe 24b is connected to the gate of an FET 28 via a bonding wire. Transmission line 2
5a is connected to one terminal of the varactor diode 29 via a bonding wire. The other terminal of the varactor diode 29 is connected to the ground electrode 27 via a bonding wire. The end of the probe 25b is an open end. A thin-film inductor 30 and a thin-film resistor 31 are formed between the connection end of the transmission line 25a to the varactor diode 29 and the bias electrode 32. Further, a chip capacitor 33 is connected between the bias electrode 32 and the ground electrode 27.

The FET 28 has a drain connected to an input electrode 35 via a microstrip line 34 as an inductor, and a source connected to one end of the microstrip line 36. A chip capacitor 40 is connected between the input electrode 35 and the ground electrode 27.

The other end of the microstrip line 36 is connected to the ground electrode 27 via a resistance film 38. Further, another microstrip line 39 is provided with a certain gap from the microstrip line 36, and an end portion thereof is used as an output electrode 41.

In this manner, a band reflection type oscillator is formed by the dielectric resonator, the main line, and the FET.
By providing a varactor diode together with a sub-line coupled to the dielectric resonator unit, a VCO whose oscillation frequency changes due to the capacitance of the varactor diode is configured.

The ceramic package 50 comprises ceramic substrates 51 and 52. Ceramic substrate 51
Is provided with a concave portion 53, and an external terminal 54 is formed so as to surround the concave portion 53. A conductor is formed on the bottom surface of the concave portion 53. This ceramic package 50
, The VCO module 21 is stored with the dielectric sheet 2 side facing down, and the input electrode 35 and the output electrode 4
1. The surface mount type VCO is formed by connecting the bias electrode 32 and the other ground electrode 27 to the external terminal 54 and sealing them with a metal plate (not shown).

Next, FIG. 6 is an exploded perspective view showing the structure of a main part of a VCO according to a fourth embodiment. Unlike the example shown in FIG. 5, in this example, a dielectric plate 3 is further placed on the dielectric sheet 2. An earth electrode 14 is formed on the upper surface of the dielectric plate 3 in the drawing, and the dielectric plate 3 is mounted on the upper part of the dielectric resonator unit, that is, at a position sandwiching the probes 24b and 25b. As a result, a so-called triplate type line composed of the dielectric plate 1, the dielectric sheet 2, and the dielectric plate 3 is formed. However, the probes 24b, 25
The portion b does not have an electrode on the dielectric plate 1 side in the lower layer, so this portion functions as a microstrip line using the ground electrode 14 on the dielectric plate 3 side as a ground electrode. in this way,
By placing the dielectric part close to the probe,
The line width for obtaining the same characteristic impedance can be reduced. Therefore, the line width of the probe portion can be reduced while keeping the impedance of the probe portion and the transmission line portion equal, and a special impedance matching section becomes unnecessary.

[0027]

Effects of the Invention According to the invention described in claim 1, the conductor area is reduced in the resonance space, the result Q _L is increased. In addition, when a high input impedance FET, for example, is connected to one end of the line, the line width can be reduced to the connection portion of the FET and the impedance of the line can be increased to facilitate impedance matching with the FET. Will be able to

According to the second aspect of the present invention, impedance mismatch between the narrow line portion coupled to the dielectric resonator portion and the other portions is prevented, and the occurrence of reflection loss and reflection are prevented. Unstable operation is prevented.

According to the third aspect of the present invention, since the other dielectric plate is close to the line provided on the sheet and the microstrip line is formed at that portion, the characteristic impedance of the line is kept constant. The line width can be reduced while keeping the distance. Therefore, it is not necessary to provide a special impedance matching unit.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a configuration of a dielectric filter according to a first embodiment.

FIG. 2 is a diagram showing a configuration of a main part of the dielectric filter.

FIG. 3 is an exploded perspective view showing a configuration of a dielectric filter according to a second embodiment.

FIG. 4 is a plan view of a main part of the dielectric filter.

FIG. 5 is an exploded perspective view showing a configuration of a main part of a VCO according to a third embodiment.

FIG. 6 is an exploded perspective view showing a configuration of a main part of a VCO according to a fourth embodiment.

FIG. 7 is a perspective view showing the configuration of a conventional VCO.

[Explanation of symbols]

 1-Dielectric plate 2-Dielectric sheet 3-Dielectric plate 4,5-Conductor plate 6,7-Line 6a, 7a-Transmission line 6b, 7b-Probe 6c-Impedance matching unit 14,15,16-Conductivity Body film 17, 18, 19, 20-Conductor non-forming portion 21-VCO module 24a, 25a-Transmission line 24b, 25b-Probe 25c-Impedance matching unit 28-FET 29-Varactor diode 50-Ceramic package R-Dielectric Resonator section

Claims (3)

[Claims] An electric conductor film is formed on both main surfaces of a dielectric plate except for a part thereof, and a portion where the electric conductor film is not formed is used as a dielectric resonator portion. In a high-frequency module in which a sheet on which a line to be partially coupled is formed is superposed on the dielectric plate, a line width of at least the line coupled to the dielectric resonator portion is made narrower than other portions. And high frequency module. 2. The high-frequency module according to claim 1, wherein an impedance matching section is provided between a portion of the line coupled to the dielectric resonator and the other portion. 3. A dielectric plate which sandwiches the sheet between the line portion and the dielectric plate.
2. The high-frequency module according to item 1.