JP3772513B2 - High frequency module - Google Patents

Description

[0001]
BACKGROUND 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 and a millimeter wave band.
[0002]
[Prior art]
With the recent increase in demand for mobile communication systems and the increase in the amount of transmission information, the communication band is being expanded to the millimeter wave band. When a dielectric filter or a voltage controlled oscillator (hereinafter referred to as VCO) is configured using a TE01δ mode dielectric resonator in such a high frequency band, the resonance frequency of a general TE01δ mode dielectric resonator is a cylinder. Since it is determined by the external dimensions of the shape dielectric, and the coupling with the microstrip line is determined by the distance between them, high dimensional accuracy and positioning accuracy are required.
[0003]
Therefore, the applicant of the present application has proposed a dielectric resonator and a dielectric filter excellent in processing accuracy which have solved these problems in Japanese Patent Application No. 7-62625.
[0004]
In the dielectric resonator and the dielectric filter according to the above application, a part of the dielectric plate is used as the 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. Thus, a high frequency module such as a VCO including a dielectric resonator and an electronic component can be configured.
[0005]
In addition, a dielectric resonator device and a high-frequency module in which a part of a dielectric plate is used as a dielectric resonator, a sheet on which a line is formed are stacked on the dielectric plate, and the dielectric resonator and the line are coupled to each other are provided. This is proposed in Japanese Patent Application No. 8-294087.
[0006]
An example of the configuration is shown in FIG. 7 as a perspective view. In FIG. 1, reference numeral 1 denotes a dielectric plate. A TE010 mode dielectric resonator section is formed by forming a conductor film on both main surfaces except for a part thereof. Reference numeral 2 denotes a dielectric or insulator sheet on which lines 24 and 25 are formed. In a state where the sheet 2 is laminated on the dielectric plate 1, the lines 24 and 25 are magnetically coupled to the dielectric resonator unit.
[0007]
[Problems to be solved by the invention]
In the conventional high-frequency module shown in FIG. 7, the characteristic impedance (hereinafter simply referred to as impedance) of the line of each part is set to 50Ω by design, and the impedance of the line coupled to the dielectric resonator part is also set to 50Ω. .
[0008]
However, in such a high-frequency module, because of its structure, a conductor line is inserted into the resonance space of the dielectric resonator section, conductor loss occurs in that portion, and the load Q of the resonator (Q _L ) decreases. In particular, since the line width of a 50Ω line is large, increasing the amount of insertion into the resonance space greatly reduces Q _L.
[0009]
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.
[0010]
SUMMARY OF THE INVENTION An object of the present invention is to provide a high-frequency module that solves the problem of lowering Q _L of a dielectric resonator section formed on a dielectric plate and that can easily achieve impedance matching with an FET or the like. .
[0011]
[Means for Solving the Problems]
According to the present invention, a conductor film is formed on almost the entire surface except for a part on both main surfaces of the dielectric plate, and a conductor film opening region whose periphery is closed by the conductor film is arranged on both main surfaces of the dielectric plate. and, a conductor film opening region facing portion between the both principal surfaces by a dielectric resonator portion, superimposed dielectric sheet to the dielectric plate, on the surface not adjacent to the dielectric plate of the dielectric sheet, the dielectric In a high-frequency module in which a line partially coupled to the resonator part is formed, at least the dielectric resonance of the line is provided in a region facing the dielectric resonator part on a surface not adjacent to the dielectric plate of the dielectric sheet. A probe portion coupled to the resonator portion is formed, another transmission line portion is formed outside the region facing the dielectric resonator portion, and the line width of the probe portion is narrower than the line width of the other transmission line portion. This reduces the conductor area inserted into the resonant space, resulting in an increase in QL. Also, when connecting, for example, an FET with high input impedance to one end of the line, the impedance can be easily matched with the FET by narrowing the line width to the connection part of the FET and increasing the line impedance. Will be able to.
[0012]
An impedance matching portion having a line width different from that of either the probe portion or the other transmission line portion is provided between the probe portion and the other transmission line portion . As a result, impedance mismatch between the probe portion with a narrow line width coupled to the dielectric resonator portion and the other transmission line portion is prevented, and generation of reflection loss and unstable operation due to reflection are prevented.
[0013]
Further, the present invention provides another dielectric plate that sandwiches the sheet between the probe portion and the dielectric plate, and substantially reduces the line impedance of the probe portion and the line impedance of the other transmission line portion. It is characterized by being equal . As a result, the other dielectric plate comes close to the probe provided on the sheet, and the triplate 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]
DETAILED DESCRIPTION OF THE INVENTION
The configuration of the bandpass filter according to the first embodiment of the present invention will be described with reference to FIGS.
[0015]
FIG. 1 is an exploded perspective view of the main part. In the figure, reference numeral 1 denotes a dielectric plate, and a conductor film is formed on the upper and lower surfaces in the figure. However, the conductor film 15 is provided on the upper surface in the figure so that the circular conductor non-forming portions 17 and 19 are formed. On the lower surface of the dielectric plate 1 in the figure, a conductor film having a conductor non-formation portion of the same shape is formed in a portion facing the conductor non-formation portions 17 and 19. With this structure, two TE010 mode dielectric resonator portions are formed on the dielectric plate sandwiched between the conductor non-forming 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 drawing. The root portions 6a and 7a of the lines 6 and 7 are transmission lines having a relatively large line width, and the portions 6b and 7b protruding from the transmission lines are probes having a narrow line width. By superposing the dielectric sheet 2 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 conductive plates 4 and 5, the dielectric resonator portion and the line are arranged between the two parallel conductive plates.
[0016]
2A and 2B are views showing a state in which a dielectric sheet is overlapped on the dielectric plate shown in FIG. 1, wherein FIG. 2A is a plan view and FIG. 2B is a central sectional view thereof. Thus, the conductor film 15 provided with the conductor non-forming portions 17 and 19 on the upper surface of the dielectric plate 1 is formed, and the conductor film provided with the conductor non-forming portions 18 and 20 on the lower surface of the dielectric plate 1. By forming 16, two TE010 mode dielectric resonator parts are formed between the conductor non-forming parts. The broken line in (B) of FIG. 6 shows the magnetic field distribution of the mode, and two adjacent dielectric resonator parts 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 a two-stage resonator is formed between the transmission lines 6a-7a.
[0017]
Here, the transmission lines 6a and 7a have an impedance of 50Ω in accordance with a circuit having an input / output impedance of 50Ω connected thereto and a line having an impedance of 50Ω. Since the line widths of the probes 6b and 7b are narrower than those of 6a and 7a, the impedance thereof is higher than 50Ω. By narrowing the line width of the probe inserted into the resonance space in this way, the conductor loss is reduced and the decrease in Q _L of the dielectric resonator portion is suppressed.
[0018]
Next, the configuration of the dielectric filter according to the second embodiment will be described with reference to FIGS.
[0019]
FIG. 3 is an exploded perspective view thereof. In the figure, reference numeral 1 denotes a dielectric plate, and a conductor film 15 is provided so that circular conductor non-formation portions 17 and 19 are formed on the upper surface in the figure. On the lower surface of the dielectric plate 1 in the figure, a conductor film having a conductor non-formation portion of the same shape is formed in a portion facing the conductor non-formation portions 17 and 19. With this structure, two TE010 mode dielectric resonator portions are formed on the dielectric plate sandwiched between the conductor non-forming portions. In FIG. 3, reference numeral 2 denotes a dielectric sheet made of PTFE or the like, and a line 6 is formed on the upper surface in the drawing. The dielectric sheet 2 is overlapped with the dielectric plate 1 on which the conductor film is formed, so that a part of the line 6 is coupled to two dielectric resonator portions. Further, by sandwiching these dielectric plates and dielectric sheets between the conductive plates 4 and 5, a dielectric resonator portion and a line are arranged between two parallel conductive plates.
[0020]
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. In this way, both end portions 6a of the line 6 are transmission lines having a relatively large line width, and the intermediate portion 6b is a probe having a narrow line width. Moreover, the impedance matching part 6c is formed in the intermediate part of a transmission line and a probe. Here, assuming that the impedance of the transmission line 6a is Za and the impedance of the probe 6b is Zb, the impedance Zc of the impedance matching unit 6c is a line width having a relationship of Zc = √ (Za · Zb), and the line length is λg / 4 (λg is the transmission line wavelength). The probe 6b is magnetically coupled to two TE010 mode dielectric resonator portions provided on the dielectric plate 1 respectively. The interval between the coupling positions is an odd multiple of λg / 4. As a result, a dielectric filter having a band rejection characteristic in which two resonators are coupled to predetermined positions of the transmission lines 6a and 6a is obtained.
[0021]
Next, the structure of the main part of the VCO according to the third embodiment is shown in FIG. 5 as an exploded perspective view. In the figure, 21 is a VCO module and 50 is a ceramic package. The dielectric plate 1 of the VCO module 21 is formed with one TE010 mode dielectric resonator section R in the same manner as shown in FIG. An FET 28 and a varactor diode 29 are mounted on the upper surface of the dielectric plate 1. On the upper surface of the dielectric sheet 2, a main line composed of a transmission line 24a, a probe 24b, and an impedance matching part 24c and a sub line composed of the transmission line 25a, the probe 25b, and the impedance matching part 25c are provided as a dielectric resonator part R. It is formed to overlap. One end of the transmission line 24a is connected to the ground electrode 27 through the resistance film 26, and the other end of the probe 24b is connected to the gate of the FET 28 through the bonding wire. The transmission line 25a is connected to one terminal of the varactor diode 29 through a bonding wire. The other terminal of the varactor diode 29 is connected to the ground electrode 27 through 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 25 a 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.
[0022]
The FET 28 has a drain connected to the 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.
[0023]
The other end of the microstrip line 36 is connected to the ground electrode 27 through a resistance film 38. Further, another microstrip line 39 is provided with a certain gap with respect to the microstrip line 36, and an end thereof is used as an output electrode 41.
[0024]
Thus, by forming a band reflection type oscillator by the dielectric resonator section, the main line, and the FET, and providing the varactor diode together with the sub line coupled to the dielectric resonator section, the capacitance of the varactor diode This constitutes a VCO whose oscillation frequency changes.
[0025]
The ceramic package 50 is composed of ceramic substrates 51 and 52. The ceramic substrate 51 is provided with a recess 53, and an external terminal 54 is formed so as to surround the recess 53. A conductor is formed on the bottom surface of the recess 53. The ceramic package 50 accommodates the VCO module 21 with the dielectric sheet 2 side facing down, and the input electrode 35, the output electrode 41, the bias electrode 32, and the other ground electrode 27 are connected to the external terminal 54, respectively. A surface-mount type VCO is configured by sealing with a metal plate (not shown).
[0026]
Next, the configuration of the main part of the VCO according to the fourth embodiment is shown in FIG. 6 as an exploded perspective view. Unlike the example shown in FIG. 5, in this example, a dielectric plate 3 is further placed on top of the dielectric sheet 2. An earth electrode 14 is formed on the upper surface of the dielectric plate 3 in the figure, and the dielectric plate 3 is placed at the upper portion of the dielectric resonator portion, 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, since the probes 24b and 25b have no electrode on the dielectric plate 1 side in the lower layer, this portion functions as a microstrip line having the ground electrode 14 on the dielectric plate 3 side as the ground electrode. Thus, by arranging the dielectric portion close to the probe, the line width for obtaining the same characteristic impedance can be reduced. For this reason, the line width of the probe portion can be narrowed while keeping the impedances of the probe portion and the transmission line portion equal, and a special impedance matching portion becomes unnecessary.
[0027]
【The invention's effect】
According to the first aspect of the present invention, the conductor region in the resonance space is reduced, and as a result, Q _L is increased. Also, when connecting, for example, an FET with high input impedance to one end of the line, the impedance can be easily matched with the FET by narrowing the line width to the connection part of the FET and increasing the line impedance. Will be able to.
[0028]
Further , impedance mismatch between the narrow probe portion coupled to the dielectric resonator portion and the other transmission line portion is prevented, and generation of reflection loss and unstable operation due to reflection are prevented.
[0029]
According to the second aspect of the present invention, since the other dielectric plate is close to the probe portion provided on the sheet and the triplate type line is formed at that portion, the characteristic impedance of the line is constant. Thus, the line width of the probe portion can be reduced. 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 a dielectric according to a second embodiment. FIG. 4 is a plan view of the main part of the dielectric filter. FIG. 5 is an exploded perspective view showing the structure of the main part of the VCO according to the third embodiment. FIG. 7 is an exploded perspective view showing the configuration of the main part of the VCO according to the embodiment. FIG. 7 is a perspective view showing the configuration of a conventional VCO.
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-conductive Body films 17, 18, 19, 20—conductor non-formation part 21—VCO modules 24a, 25a—transmission lines 24b, 25b—probe 25c—impedance matching part 28—FET
29-Varactor diode 50-Ceramic package R-Dielectric resonator part

Claims (2)

A conductor film is formed on almost the entire surface except for a part on both main surfaces of the dielectric plate, and a conductor film opening region whose periphery is closed by the conductor film is arranged on both main surfaces of the dielectric plate, The opposing portions of the conductive film opening regions of the two main surfaces are used as dielectric resonator portions, a dielectric sheet is overlaid on the dielectric plate, and the surface of the dielectric sheet not adjacent to the dielectric plate, In the high frequency module in which a line partially coupled to the dielectric resonator portion is formed,
A probe portion coupled to at least the dielectric resonator portion of the line is formed in a region facing the dielectric resonator portion on a surface of the dielectric sheet not adjacent to the dielectric plate; Another transmission line portion is formed outside the region facing the resonator portion, the line width of the probe portion is narrower than the line width of the other transmission line portion, and the probe portion and the other transmission line portion The high-frequency module is characterized in that an impedance matching portion having a line width different from that of any of the probe portion and the other transmission line portion is provided between the probe portion and the other transmission line portion. A conductor film is formed on almost the entire surface except for a part on both main surfaces of the dielectric plate, and a conductor film opening region whose periphery is closed by the conductor film is arranged on both main surfaces of the dielectric plate, The opposing portions of the conductive film opening regions of the two main surfaces are used as dielectric resonator portions, a dielectric sheet is overlaid on the dielectric plate, and the surface of the dielectric sheet not adjacent to the dielectric plate, In the high frequency module in which a line partially coupled to the dielectric resonator portion is formed,
A probe portion coupled to at least the dielectric resonator portion of the line is formed in a region facing the dielectric resonator portion on a surface of the dielectric sheet not adjacent to the dielectric plate ; form another transmission line sections outside the area facing the cavity portion, the line width of the probe portion as well as narrower than the line width of the other transmission line portion, between the dielectric plate at said probe portion A high frequency module comprising: a dielectric plate sandwiching the sheet; and the line impedance of the probe portion and the line impedance of the other transmission line portion being substantially equal.

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