JPH05243815A - Antenna sharing equipment - Google Patents

Abstract

(57) [Abstract] [Purpose] It is possible to easily configure the transmission filter and the reception filter, which have the desired characteristics separately, without lowering the desired characteristics, and is suitable for cost reduction and downsizing. Provide an antenna duplexer. A transmission filter 2 for transmitting a transmission signal of a first frequency band input from a transmission circuit via a terminal T _X to an antenna terminal ANT, and a first filter of the first frequency band input from an antenna terminal ANT. A reception filter 4 for transmitting a reception signal of the second high frequency band to a reception circuit via a terminal R _X , and a signal combination for connecting the transmission filter 2, the reception filter 4 and the antenna terminal ANT. In the antenna duplexer including the section 6, the signal combining section 6 forms a high-pass filter including inductors L ₁ and L ₂ and a capacitor C ₁ .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a demultiplexing function which is mounted on a radio or the like to supply a transmission signal output from a transmission circuit to an antenna and supply a reception signal input from the antenna to a reception circuit. Regarding antenna duplexer.

[0002]

2. Description of the Related Art Conventionally, the problems to be solved by the invention
As a high frequency band antenna duplexer, a circulator is used, or a transmission dielectric filter and a reception dielectric filter are connected by a distributed constant line as disclosed in, for example, JP-A-64-60006. However, it is known that the line is formed on a substrate.

However, the one using a circulator is disadvantageous in that it is expensive and has a large shape, which is disadvantageous in downsizing and cost reduction. Further, the above-mentioned JP-A-64-60
In the method disclosed in Japanese Patent No. 006, the line length of the distributed constant line is as long as λ / 4, which is a major obstacle to downsizing and cost reduction of the antenna duplexer. That is, for example, when a line is formed on a glass epoxy substrate having a thickness of 1 mm (dielectric constant of 4.8) with a conductor film pattern having a width of 1.8 mm so as to have a characteristic impedance of 50Ω, the line length is 836 MHz and 84 mm, 6 at 881 MHz
This requires 0 mm, which makes it difficult to reduce the size and cost. Further, when the line length changes due to an attachment error when connecting the transmission line and the transmission filter and the reception filter at the time of manufacture, the characteristics change, which causes a problem that it takes time for the adjustment process.

On the other hand, it has been considered to include a demultiplexing circuit in the transmitting filter and / or the receiving filter, but it is not possible to evaluate the characteristics of each filter alone, and it is very difficult to design and adjust the filter. It takes man-hours and is not suitable for cost reduction.

The present invention solves the problems described above, and can be easily constructed and reduced without deteriorating the desired characteristics of the transmission filter and the reception filter for which desired characteristics are obtained separately. An object of the present invention is to provide an antenna duplexer suitable for cost reduction and size reduction.

[0006]

According to the present invention, in order to achieve the above object, a first circuit input from a transmission circuit is used.
A transmission filter for transmitting a transmission signal of the frequency band of 1 to an antenna terminal, and a reception filter for transmitting a reception signal of a second frequency band higher than the first frequency band and input from the antenna terminal to a reception circuit. In an antenna duplexer including a signal synthesizing unit that connects the transmitting filter, the receiving filter, and the antenna terminal, the signal synthesizing unit forms a high-pass filter including an inductor and a capacitor. An antenna duplexer is provided.

In the present invention, preferably the first
In the frequency band and the second frequency band, the characteristics of the inductor and the capacitor are selected so that the impedance of the signal combining unit is matched to 50 ± 10Ω and the reflection coefficient phase angle is + 90 ± 25 degrees. Has been done.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an equivalent circuit diagram showing an embodiment of an antenna duplexer of the present invention, and FIG. 2 is a perspective view of its concrete structure.

In these figures, 2 is a transmitting filter, 4 is a receiving filter, and 6 is a signal combining unit. Both the transmission filter 2 and the reception filter 4 are dielectric filters. The dielectric filter comprises a plurality of dielectric resonators 10 connected in parallel via capacitors. As shown in FIG. 2, the dielectric resonator 10 has a rectangular parallelepiped dielectric block 10a provided with an outer conductor 10b on the outer surface thereof, and is formed in parallel with the surface provided with the outer conductor. The inner conductor 10c is attached to the inner surface of the through hole. A conductor film (not shown) is also attached to one end surface of the dielectric block 10a, whereby the outer conductor 10 is formed.
b and the inner conductor 10c are short-circuited. The transmitting filter 2 is connected to the transmitting circuit at the terminal T _X , and the receiving filter 4 is connected to the receiving circuit at the terminal R _X. The signal synthesizer 6 includes inductors L ₁ and L ₁ as shown in the drawing.
_A high-pass filter composed of ₂ and the capacitor C ₁ is formed, and is connected to the antenna at the terminal ANT on the transmission filter 2 side.

As shown in FIG. 2, the above-mentioned components are mounted on the insulating substrate 12. A conductor film pattern including the terminals T _X , R _X , and ANT is formed on the surface of the substrate 12, and E is a ground terminal connected to the outer conductor 10b of the all-dielectric filter 10. An insulating plate 14 and an insulating plate 16 are arranged on the substrate 12 so as to correspond to the transmitting filter 2 and the receiving filter 4, respectively. Each dielectric block 10 of each filter is provided on the surface of these insulating plates.
A conductor film piece connected to the inner conductor 10c exposed on the non-short-circuited end face is attached, and a capacitor is formed by these adjacent conductor film pieces. Further, a capacitor is formed by the terminal T _X of the transmission filter 2 and the outermost conductor film piece adjacent to the terminal T _X, and the terminal R of the reception filter 4 is formed.
_A capacitor is formed by _X and the outermost conductor film piece adjacent thereto. On the other hand, the inductors L ₁ and L ₂ of the signal synthesizing unit 6 are spiral coils, and the capacitor C ₁ of the signal synthesizing unit is a conductor film pattern.

The characteristics of the antenna duplexer having the above configuration are shown in FIGS. 3 and 4. FIG. 3 shows the frequency characteristics of the transmission side filter 2 and the reception side filter 4, and the frequency band of the transmission side filter is lower than the frequency band of the reception side filter. FIG. 4 shows frequency characteristics of the signal synthesizing unit 6.

In this antenna duplexer, the impedance of the signal combining unit 6 is matched to 50 ± 10Ω and the reflection coefficient phase angle is + 90 ± 25 degrees in both frequency bands of the transmitting side filter and the receiving side filter. It is preferable to select the characteristics of the inductor and the capacitor so that By doing so, the insertion loss is significantly reduced. For example, the impedance is 50Ω
And the inductors L ₁ and L ₂ and the capacitor C of the signal combining unit 6 are matched so that the reflection coefficient phase angle becomes +100 degrees.
_When the characteristic of ₁ is selected, the insertion loss of the transmission filter 2 and the reception filter 4 was 2.2 dB and 2.6 dB in the case of these alone, respectively. It hardly increases to 2 dB and 2.7 dB. Especially, the loss of the filter on the transmission side does not increase,
That is a great advantage.

Thus, the transmission signal input from the transmission circuit and passed through the transmission side filter 2 is transmitted to the antenna with high efficiency, and the reception signal input from the antenna does not pass through the transmission side filter 2 and the signal synthesizing unit 6 is provided. And, it is transmitted to the receiving circuit with high efficiency through the receiving side filter 4.

Further, in the present embodiment, since the signal synthesizing section 6 also exhibits the filter characteristic as described above, there is an advantage that the performance can be evaluated independently. In addition, in the present embodiment, since the accuracy at the time of connecting the transmitting side filter 2 and the receiving side filter 4 to the signal synthesizing section 6 is gradual, the transmitting side filter and the receiving side filter having desired characteristics are manufactured. By combining with a signal combining unit having desired characteristics, it is possible to obtain an antenna duplexer having desired characteristics of SWR that requires less adjustment work and is stable at low cost.

Further, the size of the signal synthesizing unit 6 of this embodiment can be made sufficiently smaller than that of the conventional one using the distributed constant line.

In the above embodiment, the high pass filter of the signal synthesizing unit 6 has one stage, but it may have multiple stages. Further, in the signal synthesizing unit, an inductor having a conductor film pattern may be used as the inductor, and a capacitor other than the conductor film pattern may be used.

[0018]

As described above, according to the present invention, by using the high-pass filter composed of the inductor and the capacitor as the signal synthesizing section for connecting the transmitting filter, the receiving filter and the antenna terminal, It is possible to obtain an antenna duplexer that can be reduced in cost and downsized without lowering the desired characteristics of the transmission filter and the reception filter that have separately obtained desired characteristics.

[Brief description of drawings]

FIG. 1 is an equivalent circuit diagram showing an embodiment of an antenna duplexer of the present invention.

FIG. 2 is a perspective view of a specific structure of the antenna duplexer of FIG.

FIG. 3 is a diagram showing characteristics of the antenna duplexer of FIG.

FIG. 4 is a diagram showing characteristics of the antenna duplexer of FIG.

[Explanation of symbols]

 2 filter for transmission 4 filter for reception 6 signal synthesizer 10 dielectric resonator 10a dielectric block 10b outer conductor 10c inner conductor

Claims (2)

[Claims] 1. A transmission filter for transmitting a transmission signal of a first frequency band input from a transmission circuit to an antenna terminal, and a second frequency band of a second frequency band higher than the first frequency band input from the antenna terminal. In an antenna duplexer including a receiving filter that transmits a received signal to a receiving circuit, and a signal combining unit that connects the transmitting filter, the receiving filter, and the antenna terminal, the signal combining unit includes an inductor and a capacitor. An antenna duplexer, which is characterized in that a high-pass filter composed of is formed. 2. In the first frequency band and the second frequency band, the impedance of the signal combiner is matched to 50 ± 10Ω and the reflection coefficient phase angle is +.
The antenna duplexer according to claim 1, wherein the characteristics of the inductor and the capacitor are selected so as to be 90 ± 25 degrees.