JP2010041263A - Antenna duplexer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antenna duplexer that reduces a manufacturing cost and improves mass productivity. <P>SOLUTION: A reception bandpass filter, a transmission bandpass filter, and a branch circuit are formed on a dielectric substrate 5 by a planar line while planar line-waveguide converters 6a, 6b, and 6c are also formed on the dielectric substrate. The reception bandpass filter, the transmission bandpass filter, and the branch circuit are connected to the corresponding transmission line, which includes waveguides formed in a first base 1 and a second base 2 via each planar line-waveguide converter 6b, 6c, and 6a. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an antenna duplexer, and more particularly to an antenna duplexer used in a microwave band and a millimeter wave band.

  Conventionally, as an antenna duplexer used in a high frequency band radio apparatus such as a microwave band and a millimeter wave band, a waveguide filter and a waveguide T-branch circuit are used as disclosed in Patent Document 1, for example. There is an antenna duplexer.

JP-A-9-270732

In general, in a waveguide filter, a half-wave resonator is formed by dividing the inside of the waveguide by an iris for each half wavelength of the used wavelength. By appropriately selecting the iris interval and the iris thickness, it is possible to realize an inter-resonator electromagnetic field coupling amount necessary for obtaining desired filter characteristics. At this time, the metal processing accuracy in manufacturing the iris greatly affects the filter characteristics, and high metal processing accuracy is required to realize a high-performance waveguide filter.
Similarly, in a waveguide T branch circuit, high metal processing accuracy is required to obtain high-performance branch characteristics.
For this reason, there existed a problem that the manufacturing cost of the antenna sharing device using a waveguide filter and a waveguide T branch circuit increased, and mass productivity was scarce.
The present invention has been made to solve such problems, and an object thereof is to provide an antenna duplexer capable of reducing the manufacturing cost and improving the mass productivity.

  An antenna duplexer according to the present invention includes a reception filter connected to a reception circuit, a transmission filter connected to a transmission circuit, and a branch circuit connected to the antenna and connected to the reception filter and the transmission filter. In the duplexer, the reception filter, the transmission filter, and the branch circuit are configured with planar lines, the transmission line that connects the reception filter and the reception circuit, the transmission line that connects the transmission filter and the transmission circuit, the branch circuit, and the antenna Each transmission line is constituted by a waveguide, and a planar line-waveguide converter is connected between a reception filter, a transmission filter, and a branch circuit and the corresponding transmission line.

A planar circuit structure is an example of a high-frequency circuit structure excellent in mass productivity. The planar circuit can realize a high frequency circuit while reducing variation in characteristics by a highly accurate thin film processing technique. In addition, the planar circuit formed on the dielectric substrate can be reduced in circuit size as compared with the three-dimensional waveguide circuit, which leads to downsizing of a device using the planar circuit.
On the other hand, in terms of the function as a transmission line, the waveguide has a low loss compared to a planar circuit such as a microstrip line, and is excellent in long-distance transmission.

Therefore, according to the present invention, a planar circuit structure is used for the reception filter, transmission filter, and branch circuit portion, which conventionally required high metal processing accuracy, and a waveguide is used for the transmission line portion that requires low loss. By using it, it is possible to realize an antenna duplexer structure excellent in electrical characteristics and mass productivity. Thereby, the manufacturing cost of the antenna duplexer can be reduced and the mass productivity can be improved.
In addition, in order to realize the transmission line portion with a waveguide, a planar line-waveguide converter that converts from a state of transmitting on a planar circuit such as a transmission / reception filter or a branch circuit to a state of transmitting within the waveguide is provided. Use. The waveguide shape used in the antenna duplexer according to the present invention does not require a complicated shape unlike conventional waveguide filters and waveguide T-branch circuits, and metal processing is easy.

  According to the present invention, the reception filter, the transmission filter, and the branch circuit are configured by planar lines, and the transmission line including the waveguide through the planar line-waveguide converter is connected to each of the reception filter, the transmission filter, and the branch circuit. Since the antenna is connected, the manufacturing cost can be reduced and an antenna duplexer with excellent mass productivity can be realized.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
1 and 2 are perspective views of the antenna duplexer according to the embodiment as viewed from the front side and the back side. A waveguide circuit is formed in the first pedestal 1 and the second pedestal 2, a waveguide 4 is formed on the surface of the first pedestal 1, and a waveguide is formed on the surface of the second pedestal 2. A wave tube 8 and a waveguide 9 are formed. A dielectric substrate 5 is bonded to the first pedestal 1 via a metal plate 7. On the substrate 5, a transmission band filter, a reception band filter, and a branch circuit are formed in a planar circuit pattern, and planar line-waveguide converters 6a, 6b, and 6c are formed.
When the substrate 5 connected to the first pedestal 1 needs to be sealed, a sealing lid 3 as shown in FIG. 1 is put on the first pedestal 1.

  In this embodiment, the waveguide 4 is described as an antenna terminal, the waveguide 8 as a transmission circuit terminal, and the waveguide 9 as a reception circuit terminal. However, a transmission band filter and a reception band filter formed on the substrate 5 are described. And by changing the arrangement of the branch circuit, it is possible to arbitrarily select the role of the three terminals.

  FIG. 3 is an exploded view showing components of the antenna duplexer according to the embodiment. In the second pedestal 2 having the waveguide 8 constituting the transmission circuit terminal and the waveguide 9 constituting the reception circuit terminal, the waveguide grooves 12a, 12b and 12c are processed. By laminating the first pedestal 1 on the second pedestal 2, the waveguide grooves 12 a, 12 b, and 12 c can operate as rectangular waveguides and can propagate signals in the waveguide. On the other hand, the first pedestal 1 having the waveguide 4 constituting the antenna terminal is formed with waveguides 11a, 11b, and 11c connected to the waveguide grooves 12a, 12b, and 12c of the second pedestal 2. Has been.

  The transmission band filter, the reception band filter, and the branch circuit formed on the substrate 5 are connected to each other by a planar line such as a microstrip line. A signal transmitted through a planar line such as a microstrip line is converted from a state of being transmitted on the planar line to a state of being transmitted through the waveguide by the planar line-waveguide converters 6a, 6b and 6c. The signal propagates through the waveguide circuit formed in the first pedestal 1 and the second pedestal 2. The substrate 5 is connected to the waveguides 11a, 11b, and 11c processed into the first pedestal 1 through a connection metal plate 7 having waveguide ports 10a, 10b, and 10c. However, the substrate 5 can also be directly connected to the waveguides 11 a, 11 b, 11 c processed into the first pedestal 1.

  FIG. 4 shows a dielectric substrate 5 on which a high-frequency circuit pattern necessary for realizing the antenna duplexer of this embodiment is formed. On this substrate 5, a transmission band filter 13, a reception band filter 14, a branch circuit 15, a planar line 16, and planar line-waveguide converters 6a, 6b, 6c are formed. The high-frequency circuit pattern constituting the transmission band filter 13, the reception band filter 14, and the branch circuit 15 can be manufactured on the substrate 5 with high accuracy by a thin film processing technique. The planar line-waveguide converters 6a, 6b, and 6c change from a state in which signals are transmitted on the planar line 16 such as a microstrip line to a state in which the traveling direction is bent 90 degrees and transmitted in the waveguide. Has the function of converting.

In the antenna duplexer of this embodiment, the antenna duplexer characteristics such as the transmission / reception filter band and the isolation between the transmission and reception circuits are determined by the high frequency circuit formed on the dielectric substrate 5. Therefore, when it is necessary to change the characteristics of the antenna duplexer, it is only necessary to replace only the dielectric substrate 5 among the components shown in FIG.
Further, in contrast to the conventional antenna duplexer in which the transmission / reception filter is constituted by a waveguide filter and a dielectric filter, the antenna duplexer according to this embodiment is low in cost since the transmission / reception filter is constituted by a planar filter. It can be manufactured with high accuracy.

  Further, in this embodiment, in the circuit arrangement shown in FIG. 4 as an example, the planar line-waveguide converter 6a is an antenna terminal, the planar line-waveguide converter 6b is a receiving circuit terminal, and the planar line-waveguide. Although the tube converter 6c is connected to the transmission circuit terminal, the role of the three terminals can be arbitrarily selected by changing the arrangement of the transmission band filter, reception band filter and branch circuit formed on the substrate 5. is there.

The metal plate 7 shown in FIG. 5 is used for joining the substrate 5 and connecting it to the first base 1. The metal plate 7 has waveguide ports 10a, 10b, and 10c. By connecting the waveguide openings 10a, 10b, and 10c of the metal plate 7 to the waveguides 11a, 11b, and 11c of the first pedestal 1, signals transmitted through the waveguide are transmitted to the first pedestal 1 and the first pedestal 1. It propagates in the waveguide formed in the two pedestals 2.
As described above, the antenna duplexer characteristics such as the transmission / reception filter band and the isolation between the transmission / reception circuits are determined by the high-frequency circuit formed on the substrate 5, so that it is necessary to change the antenna duplexer characteristics. The metal plate 7 to which the substrate 5 is bonded may be replaced. By connecting the metal plate 7 and the first pedestal 1 with screws, it is possible to easily replace the planar circuit having different antenna duplexer characteristics.

  The perspective view which looked at the 1st base 1 from the surface side and the back surface side to FIG.6 and FIG.7, respectively is shown. Both the waveguide 4 serving as an antenna terminal and the waveguide 11a connected to the waveguide port 10a of the metal plate 7 are formed so as to penetrate from the front surface to the back surface of the first base 1. The waveguides 11b and 11c communicate with waveguide grooves 12d and 12e formed on the back surface of the first pedestal 1, respectively.

  FIGS. 8 and 9 are perspective views of the second pedestal 2 as viewed from the front side and the back side, respectively. Waveguide grooves 12 a, 12 b, and 12 c are formed on the surface of the second pedestal 2. When the first pedestal 1 is laminated on the surface of the second pedestal 2, the waveguide 11 a and the waveguide 4 of the first pedestal 1 are formed at both ends of the waveguide groove 12 a of the second pedestal 2. Are connected to form a U-shaped waveguide. Similarly, when the first pedestal 1 and the second pedestal 2 are stacked, the waveguide groove 12d and the waveguide of the first pedestal 1 are formed on the waveguide 8 and the waveguide groove 12c of the second pedestal 2. 11c is connected to form an S-shaped waveguide, and the waveguide 9 and the waveguide groove 12b of the second base 2 are connected to the waveguide groove 12e of the first base 1 and the waveguide. The wave tube 11b is connected to form an S-shaped waveguide.

FIG. 10 is a cross-sectional view taken along line AA ′ of FIGS. A waveguide groove in which the waveguide 4 and the waveguide 11a formed in the first pedestal 1 are formed in the second pedestal 2 by laminating the first pedestal 1 and the second pedestal 2. It is connected to 12a to form a U-shaped waveguide, and a signal (radio wave) propagates inside the waveguide. In this embodiment, the waveguide 4 functions as a terminal connected to an external antenna.
A substrate 5 is connected to a metal plate 7 in which a waveguide port 10 a is formed, and a planar line-waveguide converter 6 a is provided on the substrate 5. By this planar line-waveguide converter 6a, signals propagated through the waveguide 4, the waveguide groove 12a, the waveguide 11a, and the waveguide port 10a are transmitted on a planar line such as a microstrip line. And is transmitted to the branch circuit 15 provided on the substrate 5.
At both ends of the waveguide groove 12a, matching elements 17a and 17b are formed for suppressing reflected waves generated when electromagnetic waves are transmitted through the waveguide bent 90 °.

FIG. 11 is a cross-sectional view taken along the line BB ′ of FIGS. A waveguide in which the first pedestal 1 and the second pedestal 2 are stacked so that the waveguide 11c and the waveguide groove 12d formed in the first pedestal 1 are formed in the second pedestal 2. It is connected to the groove 12c and the waveguide 8 to form an S-shaped waveguide, and a signal propagates inside the waveguide. In this embodiment, the waveguide 8 functions as a terminal connected to an external transmission circuit.
A substrate 5 is connected to a metal plate 7 in which a waveguide port 10 c is formed, and a planar line-waveguide converter 6 c is provided on the substrate 5. By this planar line-waveguide converter 6c, signals propagating through the waveguide 8, the waveguide groove 12c, the waveguide groove 12d, the waveguide 11c, and the waveguide port 10c are transmitted from a microstrip line or the like. The signal is converted into a state of being transmitted on the planar line and transmitted to the transmission band filter 13 provided on the substrate 5.
Note that matching elements 17c and 17d are formed at the ends of the waveguide groove 12c and the waveguide groove 12d, respectively, for suppressing reflected waves generated when electromagnetic waves are transmitted through the waveguide bent by 90 °. ing.

Similarly, by laminating the first pedestal 1 and the second pedestal 2, the waveguide 11 b and the waveguide groove 12 e formed in the first pedestal 1 are formed in the second pedestal 2. It is connected to the waveguide groove 12b and the waveguide 9 to form an S-shaped waveguide, and a signal propagates inside the waveguide. In this embodiment, the waveguide 9 functions as a terminal connected to an external receiving circuit.
A substrate 5 is connected to a metal plate 7 in which a waveguide port 10 b is formed, and a planar line-waveguide converter 6 b is provided on the substrate 5. By this planar line-waveguide converter 6b, signals propagating through the waveguide 9, the waveguide groove 12b, the waveguide groove 12e, the waveguide 11b, and the waveguide port 10b are transmitted from a microstrip line or the like. The signal is converted into a state of being transmitted on the plane line and transmitted to the reception band filter 14 provided on the substrate 5.
Note that matching elements 17e and 17f are formed at the ends of the waveguide groove 12b and the waveguide groove 12e, respectively, for suppressing reflected waves generated when electromagnetic waves are transmitted through the waveguide bent by 90 °. ing.

  Each of the matching elements 17a to 17f has a single step shape. However, in order to obtain desired characteristics, the matching elements 17a to 17f may have a two step shape as shown in FIG. The step shape can also be made. It is also effective to use a matching element having an inclined surface shape as shown in FIG.

As a design example of the antenna duplexer having the above structure, the calculation results of the antenna duplexer characteristics designed using the high-frequency circuit simulator are shown below.
FIG. 14 shows the result of calculation of the transmission characteristics of the U-shaped waveguide extending from the waveguide port 10a shown in FIG. 10 to the waveguide 4 by electromagnetic field analysis using the finite element method. By optimally selecting the dimensions of the matching elements 17a and 17b, transmission characteristics with less reflection can be obtained as shown in FIG.
FIG. 15 shows transmission characteristics of the S-shaped waveguide extending from the waveguide port 10c to the waveguide 8 and the S-shaped waveguide extending from the waveguide port 10b to the waveguide 9 shown in FIG. Is a result of calculation by electromagnetic field analysis by the finite element method. By optimally selecting the dimensions of the matching elements 17c, 17d, 17e, and 17f, transmission characteristics with less reflection can be obtained as shown in FIG.

FIG. 16 shows the transmission characteristics of the specific circuit shapes of the planar line-waveguide converters 6a, 6b and 6c arranged as shown in FIG. 4 by electromagnetic field analysis by the finite element method. It is the result.
FIG. 17 shows a circuit pattern formed on the substrate 5 in this design example. The transmission band filter 13 and the reception band filter 14 are each realized by a microstrip line resonator coupling filter, and the branch circuit 15 is realized by a microstrip line T branch pattern. However, other high-frequency patterns may be formed on the substrate 5 as long as desired filter characteristics and branch characteristics can be obtained.
FIG. 18 shows the calculation result of the band pass filter designed as the transmission band filter 13 of FIG. 17, and FIG. 19 shows the calculation result of the band pass filter designed as the reception band filter 14 of FIG.

  Transmission characteristics of the U-shaped waveguide shown in FIG. 14, transmission characteristics of the S-shaped waveguide shown in FIG. 15, transmission characteristics of the planar line-waveguide converter shown in FIG. From the transmission characteristics of the transmission band filter shown in FIG. 18 and the transmission characteristics of the reception band filter shown in FIG. 19, the calculation results of the transmission characteristics when the antenna duplexer shown in FIG. 1 and FIG. Is shown in FIG. At this time, the antenna duplexer characteristics are optimized by appropriately selecting the line dimensions of the T branch circuit portion.

20, S31 indicates the pass characteristic from the waveguide 8 constituting the transmission circuit terminal of FIG. 2 to the waveguide 4 constituting the antenna connection terminal of FIG. 1, and S23 is the antenna connection terminal of FIG. 2 shows the passage characteristic from the waveguide 4 constituting the receiver to the waveguide 9 constituting the receiving circuit terminal of FIG. A characteristic substantially equivalent to the characteristic of the bandpass filter shown in FIGS. 18 and 19 is obtained.
S33 shows the reflection characteristics in the waveguide 4 constituting the antenna connection terminal, and it can be seen that characteristics with little reflection are obtained in the transmission band and the reception band.
S21 indicates the amount of isolation between the waveguide 8 constituting the transmission circuit terminal of FIG. 2 and the waveguide 9 constituting the reception circuit terminal, and has high isolation characteristics from the transmission circuit to the reception circuit. It was confirmed that

  As described above, it has been confirmed by circuit simulation that an excellent antenna duplexer in a high frequency band can be realized even if the transmission band filter, the reception band filter, and the branch circuit are each formed with a planar circuit pattern.

In the present invention, the functions of the waveguide filter and the waveguide T-branch circuit, which conventionally required high-precision metal processing, are realized by a planar circuit excellent in mass productivity, and the planar circuit is connected to the external circuit connection line. Since a low-loss waveguide is used through the waveguide conversion circuit, it is possible to realize an antenna duplexer that is lower in manufacturing cost and superior in mass productivity than in the past.
The antenna duplexer characteristics such as the transmission / reception filter band and the isolation between the transmission / reception circuits in the antenna duplexer of the present invention are determined by the high frequency circuit formed on the dielectric substrate. Therefore, if you want to change the characteristics of the antenna duplexer, you only need to replace the metal plate to which the dielectric substrate is bonded. Furthermore, by connecting the metal plate and the pedestal with screws, It is possible to easily exchange different planar circuits.
In addition, the planar circuit formed on the dielectric substrate can be reduced in circuit size as compared with the three-dimensional waveguide circuit, which leads to downsizing of a device using the planar circuit.

It is the perspective view which looked at the antenna sharing device which concerns on embodiment of this invention from the surface side. It is the perspective view which looked at the antenna sharing device which concerns on embodiment from the back surface side. It is an exploded view which shows the component of the antenna sharing device which concerns on embodiment. It is a perspective view which shows the dielectric substrate used in embodiment. It is a perspective view which shows the metal plate used by embodiment. It is the perspective view which looked at the 1st base used in the embodiment from the surface side. It is the perspective view which looked at the 1st base used in the embodiment from the back side. It is the perspective view which looked at the 2nd base used in an embodiment from the surface side. It is the perspective view which looked at the 2nd base used in the embodiment from the back side. It is sectional drawing of the AA 'part of FIG. It is sectional drawing of the BB 'part of FIG. It is a fragmentary sectional view which shows the modification of the element for a matching. It is a fragmentary sectional view which shows the other modification of the element for a matching. 11 is a graph showing a calculation result of transmission characteristics of a U-shaped waveguide extending from the waveguide port 10a to the waveguide 4 in FIG. 12 is a graph showing transmission characteristic calculation results of the S-shaped waveguide extending from the waveguide port 10c to the waveguide 8 and the S-shaped waveguide extending from the waveguide port 10b to the waveguide 9 in FIG. . It is a graph which shows the transmission characteristic calculation result of the planar line-waveguide converter in FIG. It is a perspective view which shows the planar circuit pattern of the reception filter, transmission filter, and branch circuit which were used in the design example. It is a graph which shows the transmission characteristic calculation result of the transmission band filter used in the design example. It is a graph which shows the transmission characteristic calculation result of the receiving band filter used in the design example. It is a graph which shows the transmission characteristic calculation result of the antenna sharing device which concerns on embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 1st base, 2nd base, 3 lid | cover for sealing, 4,8,9,11a-11c waveguide, 5 dielectric substrate, 6a-6c planar line-waveguide converter, 7 metal Plate, 10a to 10c Waveguide opening, 11a to 11c Waveguide, 12a to 12e Waveguide groove, 13 Transmission band filter, 14 Reception band filter, 15 Branch circuit, 16 Planar line, 17a to 17f Matching element.

Claims (1)

In an antenna duplexer having a reception filter connected to a reception circuit, a transmission filter connected to a transmission circuit, and a branch circuit connected to an antenna and connected to the reception filter and the transmission filter,
The reception filter, the transmission filter, and the branch circuit are configured with a planar line,
A transmission line that connects the reception filter and the reception circuit, a transmission line that connects the transmission filter and the transmission circuit, and a transmission line that connects the branch circuit and the antenna are each constituted by a waveguide,
An antenna duplexer, wherein a planar line-waveguide converter is connected between the reception filter, the transmission filter, and the branch circuit and the corresponding transmission line.

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