JP2001127665A - Transmission reception control circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transmission/reception control circuit that is compatible with dual band where a loss is small in transmission/reception and the isolation between a transmission terminal and a reception terminal can be increased in the transmission. SOLUTION: A coil 29 providing a high impedance to a reception signal is provided between a 1st transmission line 3 of a 1st switching circuit S1 and a 2nd transmission line 13 of a 2nd switching circuit S2, and 1st, 2nd and 4th switching elements 8, 4, 14 are conductive in the 1st transmission and 2nd, 3rd and 4th switching elements 4, 14, 18 are conductive in the 2nd transmission.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a transmission / reception control circuit,
In particular, the present invention relates to a dual band compatible transmission / reception control circuit.

[0002]

2. Description of the Related Art A transmission / reception control circuit is used for switching a connection between an antenna and a transmission circuit and between a reception circuit in a portable telephone or the like corresponding to two different transmission / reception frequency bands.

As a configuration of this transmission / reception control circuit, a combination of a diplexer D and two switch circuits S1 and S2 is used. Then, the reception signal from the antenna ANT is supplied to the reception circuit RX via the first or second reception terminal of the transmission / reception control circuit. The transmission signal from the transmission circuit TX is transmitted to the antenna ANT via the first or second transmission terminal of the transmission / reception control circuit and the transmission / reception control circuit.
Is paid to.

[0004] Such switching circuits S1, S2
FIG. 9 shows a circuit diagram of a conventional transmission / reception control circuit using a PIN diode as a switch element.

The first transmitting terminal 124 is connected to the capacitor 111
Is connected to the anode side of the PIN diode. The cathode side of the PIN diode 108 is connected to the second terminal 131 of the diplexer 101 via the capacitor 102 and to the transmission line 103.

[0006] The transmission line 103 is connected to the first transmission terminal 12.
4 has a line length that is λ / 4 of the first transmission signal input to the first reception signal 123, and is connected to the first reception terminal 123 via the capacitor 107. The receiving terminal of the transmission line 103 is connected to the anode of the PIN diode 104, and the cathode of the PIN diode 104 is grounded. A bias current for turning on / off the PIN diodes 104 and 108 as a switch element is:
It is supplied to the first control terminal 127. Actually, the power is supplied from the first control terminal 127 to the anode side of the PIN diode 108 and the anode side of the PIN diode 104 via the resistor 110 and the coil 9.

The capacitor 102 is a coupling capacitor for preventing a bias current flowing through the PIN diodes 108 and 104 from flowing out to the diplexer 101. The capacitors 107 and 111 are
This is a coupling capacitor for preventing a bias current flowing through the IN diodes 108 and 104 from flowing out to the transmission circuit and the reception circuit.

The coil 109 maintains a high impedance state between the first control terminal 127 and the first transmission terminal 124,
The signal (first transmission signal) supplied from the first transmission terminal 124 is prevented from flowing to the first control terminal 127.

Similarly, a circuit connected via the capacitor 112 of the third terminal 132 of the diplexer 101
The configuration is the same as that of the above-described first transmitting / receiving circuit. However, the transmission line 113 has a line length that is λ / 4 of the second transmission signal input to the second transmission terminal 126.

For example, in a first transmitting / receiving circuit,
When a first transmission signal is transmitted from the first transmission terminal 124, a positive voltage applied from the first control terminal 127 is supplied, a bias current flows through the PIN diodes 104 and 108, and the PIN diodes 104 and 108 are turned on. From this, the diplexer 10
PI between the first second terminal 131 and the first transmission terminal 124
The connection is made by the N diode 108 with almost no loss.

The transmission line 103 has an on-state PIN
Since it is grounded through the diode 104, it operates as a short stub. Then, since the transmission line 103 has a line length that is λ / 4 of the first transmission signal, a high impedance state is established between the second terminal 131 and the first reception terminal 123 of the diplexer 101, and substantially. It will be in a state of being cut off.

Therefore, the first transmission signal supplied from the first transmission terminal 124 hardly flows to the first reception terminal 124 and almost flows to the second terminal 131 of the diplexer 101.

The first transmission signal supplied to the second terminal 131 of the diplexer 101 is applied to the first terminal of the diplexer 101.
Is output to the antenna terminal 122 via the terminal 130 of FIG.

[0014] Also, at the time of transmission / reception of the second transmission signal, the circuit operates in the same manner as the above-described circuit.

At the time of receiving the first reception signal, the first reception signal
A negative reverse bias voltage is applied to the control terminal 127 of
In the OW state, the PIN diodes 104 and 108 are both turned off. Thus, the first transmission terminal 124 and the second terminal 131 of the diplexer 101 are substantially disconnected. Also, the second terminal 31 of the diplexer 101
The transmission line 103 between the first receiving terminal 123 and the second receiving terminal 123 of the diplexer 101 is connected with almost no loss.

Therefore, the first reception signal input from the antenna terminal 122 hardly flows to the first transmission terminal 124 via the diplexer 101 and is transmitted to the first reception terminal 123.

At the time of receiving the second reception signal, the PIN diodes 14 and 18 are turned off, so that the second reception signal hardly flows to the second transmission terminal 126 and is transmitted to the second reception terminal 125. You.

As described above, the first transmission / reception signal can be switched by the voltage applied to the first control terminal 127, and the second transmission / reception signal can be switched by the voltage applied to the second control terminal 128. It becomes a transmission / reception control circuit.

[0019]

In the transmission / reception control circuit having the conventional structure, when transmitting the first transmission signal, the PIN diodes 104 and 108 are biased by the positive voltage applied from the first control terminal 127. Flows into the ON state. The connection between the second terminal 131 of the diplexer 101 and the first transmission terminal 124 is almost zero. Also, the second terminal 131 of the diplexer 101
A transmission line 103 operating as a short stub exists between the first receiving terminal 123 and the first receiving terminal 123.
23 does not flow the first transmission signal. Also, since the transmission line 103 has a line length that is λ / 4 of the first transmission signal, the second terminal 13 of the diplexer 101
1 and the first receiving terminal 123 are in a high impedance state, and the second terminal 131 of the diplexer 1 and the first receiving terminal 123 are separated.

However, at the time of transmitting the first transmission signal, the first transmission signal supplied from the first transmission terminal 124 is not transmitted to the second terminal of the diplexer 101 due to slight mismatch generated in the diplexer 101. 131 and 3rd
Slightly reflected by the terminal 132 of

Further, noise having the same frequency as the first transmission frequency, which has entered the antenna from another signal source, is output from the antenna terminal 122 to the second terminal 131 and the third terminal 132 of the diplexer 101.

As a result, the signal reflected to the second terminal 131 of the diplexer 101 and the noise input from another signal source are converted to a first reception terminal 23 by applying a positive voltage to the first control terminal 127. Hardly transmits a reflected signal and noise.

However, the third of the diplexer 101
The signal reflected to the terminal 132 and noise input from another signal source leak the first transmission signal and noise to the second transmission terminal 126 by applying a positive voltage from the second control terminal 128. .

Conversely, when a negative reverse bias voltage is applied to the second control terminal 128 or when the PIN diodes 114 and 118 are turned off in the LOW state, the diplexer 10 is turned off.
The signal reflected to the first third terminal 132 and noise input from another signal source leak to the second receiving terminal 125.

Further, during transmission of the second transmission signal, the second transmission signal input from the second transmission terminal 126 is slightly mismatched in the diplexer 101 and the second terminal 131 of the diplexer 101 And the third terminal 13
2 and slightly further reflected by the second terminal 131 of the diplexer 101.

Further, noise having the same frequency as the second transmission frequency incident on the antenna from another signal source is output from the antenna terminal 122 to the second terminal 131 and the third terminal 132 of the diplexer 101.

The signal reflected to the third terminal 132 of the diplexer 1 and noise inputted from another signal source are almost reflected to the second receiving terminal 125 by applying a positive voltage to the second control terminal 128. Signal and noise are not transmitted.

However, the second diplexer 101
The signal reflected to the terminal 131 and noise input from another signal source leak the first transmission signal and noise to the first transmission terminal 126 by applying a positive voltage from the first control terminal 127. .

Conversely, when a negative reverse bias voltage is applied to the first control terminal 127 or the PIN diodes 104 and 108 are both turned off in the LOW state, the signal reflected to the second terminal 31 of the diplexer 1 and another signal Noise input from the signal source leaks to the first receiving terminal 123.

Here, in a transmission / reception control circuit for performing transmission / reception signal processing in a dual-band portable telephone, when transmitting the first transmission signal, the first transmission terminal 124 is connected to the first reception terminal 124 at the frequency of the first transmission signal. Terminal 123
Between the first transmitting terminal 124 and the second receiving terminal 125,
Between the first transmission terminal 124 and the second transmission terminal 126, between the antenna terminal 122 and the first reception terminal 123, between the antenna terminal 122 and the second reception terminal 125,
Isolation between the second and second transmission terminals 126 is required.

Similarly, at the time of transmission of the second transmission signal, at the frequency of the second transmission signal, between the second transmission terminal 126 and the first reception terminal 123, and between the second transmission terminal 12
6, between the second receiving terminal 125, between the second transmitting terminal 124 and the second transmitting terminal 126, between the antenna terminal 22 and the first receiving terminal 123, between the antenna terminal 122 and the second receiving terminal 125, Terminal 122 and first transmission terminal 123
Isolation between them is required.

However, in the conventional transmission / reception control circuit, as described above, when transmitting the first transmission signal, the first transmission terminal 124 is connected to the second transmission terminal 124 by applying a positive voltage to the second control terminal 128. When the isolation between the transmission terminals 126 is deteriorated and a negative reverse bias voltage is applied to the second control terminal 128 or the second control terminal 128 is set to a LOW state, the isolation between the first transmission terminal 124 and the second reception terminal 125 is decreased. There was a problem that became worse.

Further, at the time of transmitting the second transmission signal,
By applying a positive voltage to the first control terminal 127, the isolation between the second transmission terminal 126 and the first transmission terminal 124 is deteriorated, and conversely, a negative reverse bias voltage is applied to the first control terminal 127. Or, if it is in the LOW state, the second
There is a problem that the isolation between the transmission terminal 126 and the first reception terminal 123 becomes worse.

The present invention has been devised in view of the above-described problems, and has as its object to provide a dual-band portable telephone which can perform isolation in transmission and reception terminals even when performing transmission in each frequency band. Also, while ensuring sufficient isolation between the antenna terminal and each transmission / reception terminal, there is no increase in loss from each transmission terminal to the antenna terminal, and noise signals supplied to the transmission signal can flow to other terminals. An object of the present invention is to provide a transmission / reception control circuit having no transmission / reception control circuit.

[0035]

The present invention provides an antenna terminal to which an antenna is connected, first and second transmitting terminals to which a transmitting circuit is connected, and first and second terminals to which a receiving circuit is connected. A reception terminal, restricting a transmission signal input from the transmission circuit to a predetermined transmission frequency band and outputting the signal to the antenna, and restricting a reception signal received by the antenna to a predetermined reception frequency band and receiving the signal; A diplexer for outputting a signal to a circuit, a first switch element connected between the first transmission terminal and the diplexer,
A first terminal connected between the receiving terminal and the diplexer
A first transmission line having a line length of λ / 4 of the transmission signal, a second switch element connected between a first reception terminal side of the first transmission line and a ground electrode, A third switch element connected between a second transmission terminal and the diplexer, and a line length of λ / 4 of a second transmission signal connected between the second reception terminal and the diplexer , A fourth switch element connected between the second reception terminal side of the second transmission line and the ground electrode, and first and second controls for controlling transmission and reception. And a terminal, and connected between the first transmission line and the second transmission line via a coil, and when transmitting the first transmission signal, the first, second, and fourth transmission lines are transmitted. When the switch element is turned on and the second transmission signal is transmitted, the second, A transmission / reception control circuit characterized in that third and fourth switch elements are turned on.

The coil is formed of a meander line pattern or a winding line.

[0037]

The transmission / reception control circuit according to the present invention turns on a first switch element between a first transmission terminal and an antenna terminal to transmit a first transmission signal, and transmits the first transmission signal to the antenna terminal and the first reception terminal. Even if the first transmission line having the line length of λ / 4 of the first transmission signal between the first transmission line and the second transmission line is operated as a short stub,
By adding a coil having a sufficiently high impedance to the transmitted / received signal, the isolation of the transmitted / received signal between the first transmission line and the second transmission line can be sufficiently ensured.

Further, the fourth switch element can be turned on while the second switch element between the second transmitting terminal and the antenna terminal is turned off. That is, the antenna terminal and the second
A second transmission line having a line length of λ / 4 of the second transmission signal between the second transmission line and the receiving terminal of the second transmission signal can be operated as a shot stub.

Therefore, the first transmission signal can be transmitted from the first transmission terminal to the antenna terminal with little increase in loss, and between the first transmission terminal and the first reception terminal and between the first transmission terminal and the second transmission terminal. Can be maintained, and the isolation between the first transmission terminal and the second reception terminal can be improved.

In addition, the isolation between the antenna terminal and the second reception terminal against noise having the same frequency as that of the first transmission signal having another signal source can be improved.

Also, at the time of transmitting the second transmission signal, similar to the transmission of the first transmission signal, it is possible to transmit the second transmission signal with little increase in loss from the second transmission terminal to the antenna terminal. In addition, the isolation between the second transmission terminal and the second reception terminal, the isolation between the second transmission terminal and the first transmission terminal can be maintained, and the isolation between the second transmission terminal and the first reception terminal can be maintained. Can also be better.

In addition, the isolation between the antenna terminal and the first reception terminal against noise having the same frequency as that of the second transmission signal having another signal source can be improved.

[0043]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A transmission / reception control circuit according to the present invention will be described in detail with reference to the drawings.

FIG. 8 is a block circuit diagram of a typical transmission / reception control circuit, and FIG. 1 is a circuit diagram of a transmission / reception control circuit of the present invention.

In FIG. 8, the transmission / reception control circuit includes a diplexer D, a switching circuit S1 for performing a switching process of a first transmission / reception signal, and a switching circuit S2 for performing a switching process of a second transmission / reception signal. The first receiving terminal of the first switching circuit S1 is connected to the first receiving circuit, and the second switching circuit S1 is connected to the first receiving terminal.
A second receiving circuit is connected to the second receiving terminal 2. The first transmission circuit of the first switching circuit S1 is connected to a first transmission circuit, and the second transmission terminal of the second switching circuit S2 is connected to a second transmission circuit. In FIG. 8, the first receiving circuit and the second receiving circuit are indicated by the same receiving circuit RX, and the first transmitting circuit and the second transmitting circuit are indicated by the same transmitting circuit TX. I have.

In the transmission / reception control circuit of the present invention shown in FIG.
The diplexer D (1) is connected to the first antenna connected to the antenna 22.
, A second terminal 31 connected to the first switching circuit S1, and a third terminal 32 connected to the switching circuit S2.

In the switching circuit S1, a first transmission line 3, a PIN diode 4, which is a second switch element, and a capacitor 7 are connected between the capacitor 2 and the first receiving terminal 23. Also, the first transmission terminal 2
A capacitor 11 and a PIN diode 8 as a first switch element are connected between the capacitor 4 and the capacitor 2.

At the same time, the coil 9 and the resistor 10 are connected between the first control terminal 27 and the PIN diode 8.

The first transmitting terminal 24 is connected to the anode of the PIN diode 8 via the capacitor 11, and the cathode of the PIN diode 8 is connected to the second terminal 31 of the diplexer 1 via the capacitor 2. I have.

This transmission line 3 is λ / λ with respect to the central frequency of the first transmission signal input to the first transmission terminal 24.
It has a line length of four. Also, transmission line 3
Is connected to the first receiving terminal 23 via the capacitor 7.

The end of the transmission line 3 on the receiving terminal side is PIN
The diode 4 is connected to the anode side, and the cathode of the PIN diode 4 is grounded.

The PIN diodes 4 and 8 are connected to the first
Operate as a switch element that is turned on / off by a bias current supplied from the control terminal 27 of the control circuit. Incidentally, the bias current is supplied from the first control terminal 27 via the resistor 10 and the coil 9.

Here, the capacitor 2 is a coupling capacitor for preventing a bias current from flowing out to the ground or the outside of the transmission / reception control circuit via the diplexer 1 and a part of the diplexer 1. The capacitors 7 and 11 are coupling capacitors for preventing the current from flowing into the transmission circuit and the reception circuit. The coil 9 is used to maintain a high impedance state between the first control terminal 27 and the transmission terminal 24 and to prevent the first transmission signal from flowing to the control terminal 27.

For example, when transmitting the first transmission / reception signal, a bias current for turning on the PIN diode 8 and the PIN diode 4 is supplied to the first control terminal 27. Thereby, the first transmission line 3 is grounded via the PIN diode 4 in the ON state, and operates as a short stub. Thus, the first transmission line 3 has a high impedance with respect to the first transmission signal, and the first transmission signal is not transmitted to the first reception terminal 23.

At the time of reception, the PIN diode 8,
A bias current that is turned off (including a case where no bias current is supplied) is supplied to the PIN diode 4. Thus, the first transmission line 3 is simply a transmission line. Further, the PIN diode 8 is turned off. As a result, the first reception signal does not flow toward the first transmission terminal 24 and the first control terminal 27, but is transmitted to the first reception terminal 23 via the first transmission line 3. .

Further, the capacitor 12, the second transmission line 1
3. a PIN diode 14, which is a fourth switch element;
A second switching circuit S2 including a capacitor 17, a capacitor 21, a PIN diode 18, which is a third switching element, a coil 19, and a resistor 20, has the same configuration. However, the line length of the second transmission line 13 is set so as to correspond to the length of λ / 4 with respect to the central frequency of the second transmission signal.

Here, in this embodiment, the first transmission line 1
3 and one end of the second transmission line 13 via a coil 29. For example, in FIG. 1, a diplexer-side end of the first transmission line 3 on the first switching circuit S1 side (an arbitrary point from the cathode side of the PIN diode 8 to the anode side of the PIN diode 4),
A coil 29 connects between the diplexer-side end of the second transmission line 13 on the second switching circuit S2 side (an arbitrary point from the cathode side of the PIN diode 18 to the anode side of the PIN diode 14). I have. The connection of the coil 29 is made between the other ends of the first and second transmission lines 3 and 13 and between the first and second transmission lines 3 and 13.
You may connect to arbitrary positions, such as a part.

At the time of transmitting the first transmission signal, a bias current flows through the PIN diodes 4 and 8 due to the positive voltage applied from the first control terminal 27, and each of the PIN diodes 4 and 8 is turned on. . At the same time, coil 2
9, the above-described bias current also flows to the anode side of the PIN diode 14, and as a result, the PIN diode 14 as the fourth switch element is turned ON.

Therefore, in the first switching circuit S1, as described above, the second terminal 3 of the diplexer 1
1 and the first transmission terminal 24, a PIN diode 8
Thus, the connection is made with almost no loss.

The transmission line 3 between the second terminal 31 and the first receiving terminal 23 of the diplexer 1
The transmission line 3 operates as a short stub because it is grounded by the diode 4, and the transmission line 3
Since the line length is / 4, the impedance between the second terminal 31 and the first receiving terminal 23 of the diplexer 1 is high. As a result, the second diplexer 1
Terminal 31 and the first receiving terminal 23 are disconnected.

Therefore, the first transmission signal supplied to the first transmission terminal 24 hardly flows to the first reception terminal 24 and almost flows to the second terminal 31 of the diplexer 1.

As a result, the first transmission signal input to the first transmission terminal 24 is applied to the first terminal 30 of the diplexer 1.
Is output to the antenna terminal 22 via the.

At the same time, in the second switching circuit S2, a negative reverse bias voltage is applied to the second control terminal 28, or the PIN diode 18 is turned off in a LOW state, so that the second transmission terminal 26 and the diplexer 1 are connected to each other. Third
Between the terminals 32 is disconnected.

The coil 29 transmits the first transmission / reception signal,
A high-impedance coil is used so that a signal is not transmitted through the coil 29. And the PIN in the ON state
The second receiving terminal 2 of the transmission line 13 is controlled by the diode 14.
The five end portions are grounded.

Therefore, the reflected wave of the first transmission signal generated in the diplexer 1 and the first wave input from the antenna
Noise of the same frequency as the transmission signal of
Is hardly flown to the second receiving terminal 25 because the receiving terminal side is grounded. Further, at the time of transmitting the second transmission signal, the PIN diodes 4, 14, and 18 are turned on by a positive voltage applied from the second control terminal 28,
Applying a negative reverse bias voltage to the first control terminal 27,
The PIN diode 18 is turned off in the LOW state.

As a result, the second transmission signal input to the second transmission terminal 26 hardly flows to the second reception terminal 25 and almost flows to the third terminal 32 of the diplexer 1. Then, the second transmission signal input to the third terminal 32 of the diplexer 1 is applied to the first terminal 30 of the diplexer 1.
Is output to the antenna terminal 22 via the.

As the coil 29, a coil having a high impedance is used so that the second transmission / reception signal is not transmitted through the coil 29. Therefore, the reflected wave of the second transmission signal generated by the diplexer 1 and noise having the same frequency as the second transmission signal input from the antenna are transmitted to the first reception terminal 23 by the transmission line 3 operating as a short stub. It hardly flows.

At the time of receiving the first reception signal, a negative reverse bias voltage is applied to the first control terminal 27 and the second control terminal 28, or the LOW state is set, and the PIN diode 4,
8, 14, and 18 are turned off.

As a result, the state between the first transmission terminal 24 and the second terminal 31 of the diplexer 1 is cut off. Further, the transmission line 3 between the second terminal 31 of the diplexer 1 and the first receiving terminal 23 allows the second terminal 31 of the diplexer 1 to be connected.
And the first receiving terminal 23 are connected with almost no loss.

Since the high-impedance coil 29 is interposed between the second terminal 31 of the diplexer 1 and the second switching circuit S2, the first reception signal is completely transmitted to the second reception circuit S2. It does not appear at the terminal 25 and the second transmission terminal 26.

Therefore, the first reception signal input from the antenna terminal 22 hardly flows to the second reception terminal 25, the second transmission terminal 26, and the first transmission terminal 24,
The signal is transmitted to the first receiving terminal 23.

Similarly, when the second reception signal is received, the state between the second transmission terminal 26 and the second terminal 32 of the diplexer 1 is cut off. The transmission line 13 between the second terminal 32 and the second receiving terminal 25 of the diplexer 1 allows the connection between the second terminal 32 and the second receiving terminal 25 of the diplexer 1 with little loss. Become.

As described above, by the coil 29,
The second reception signal does not appear at the first reception terminal 23 and the first transmission terminal 24.

Therefore, the second reception signal input from the antenna terminal 22 hardly flows to the first reception terminal 23, the first transmission terminal 24, and the second transmission terminal 26,
The signal is transmitted to the second receiving terminal 25.

With respect to the coil 29 in the circuit diagram of FIG.
As shown in FIG. 1, an example constituted by a meander line pattern is shown.

Here, the meander line 143 and the input / output electrodes 141 and 142 of the meander line 143 are connected to the circuit board 1
Although it is on the surface layer 40, part or all of the meander line 143 and the input / output electrodes 141, 142 of the meander line 143 may be formed in the circuit board 140.

The coil 29 in the circuit diagram of FIG. 1 may use a winding pattern as shown in FIG. In this winding pattern, as shown in an exploded perspective view of the circuit board, between the first dielectric layer 154 and the second dielectric layer 155, and between the second dielectric layer 155 and the third dielectric layer 155. Winding patterns 161 and 162 are formed between the body layers 156 and 156, respectively.

Then, the first winding pattern 161 and the second
Between the winding pattern 162 and the via hole conductor 160
To join. Thereby, the first winding pattern 161 and the second winding pattern 162 operate as one coil.

Reference numerals 158 and 159 denote input / output ends of the winding line. These input / output ends 158 and 159 are used for the transmission / reception control circuit, for example, the first transmission line 3 and the second transmission line 13. Each is connected to one end on the diplexer side.

A predetermined wiring pattern and a transmission line 3 constituting the transmission / reception control circuit shown in FIG. 1 are provided on the surface or inside of the single-plate circuit board shown in FIG. 2 or the multilayer circuit board shown in FIG.
13 may be formed simultaneously.

[0081]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present inventor has set the frequency band of the first transmission / reception signal handled by the first switching circuit S1 to 880-915M.
A transmission / reception control circuit was prepared in which the frequency band of the second transmission / reception signal handled by the second switching circuit S2 was 1710 to 1910 MHz.

Then, 2.6 V is applied to the first control terminal 27 (127) (the diodes 8, 4, and 14 are in the ON state).
Was applied to the second control terminal 28 (128) at 0 V (the diode 18 is in the OFF state), and the transmission loss to the antenna terminal when the first transmission signal was transmitted was examined.

As a result, in the conventional transmission / reception control circuit shown in FIG.
The transmission loss up to 22 was 1.0 dB. On the other hand, in the transmission / reception control circuit of the present invention, the first transmission terminal 24
From the antenna terminal 22 to the antenna terminal 22 was similar to 1.0 dB.

The isolation between the terminals of the conventional transmission / reception control circuit shown in FIG. 9 was compared with the isolation of the transmission / reception control circuit of the present invention.

For example, with respect to the isolation from the first transmission terminal 24 (124) to the first reception terminal 23 (123), there is no change of 28.4 dB, but
From the first transmission terminal 24 (124) to the second reception terminal 25
The isolation up to (125) increases from 33.2 dB to 34.5 dB, and the antenna terminal 22 (122)
The isolation to the receiving terminal 25 (125) is 3
It improved from 1.7 dB to 34.0 dB.

FIG. 4 shows a case where the first transmission terminal 24 (124) to the second reception terminal 25 (12
The transmission characteristics up to 5) are shown.

FIG. 4A shows the transmission characteristics of the conventional transmission / reception control circuit, and FIG. 4B shows the transmission characteristics of the transmission / reception control circuit of the present invention. In this characteristic diagram, 2.6 V is applied to the first control terminal 27 (127), and the second control terminal 28 (1
0) was applied to 28).

FIG. 5 shows the antenna terminal 22 (12
The transmission characteristics from 2) to the second receiving terminal 25 (125) are shown. FIG. 5A shows the transmission characteristics of the conventional transmission / reception control circuit, and FIG. 5B shows the transmission characteristics of the transmission / reception control circuit of the present invention. Note that this characteristic diagram shows that the first control terminal 27
9 shows transmission characteristics from the first transmission terminal 24 to the second reception terminal 25 when 2.6 V is applied and 0 V is applied to the second control terminal 28.

Further, 0V is applied to the first control terminal 27 (127).
When 2.6 V is applied to the second control terminal 28 (128), the second transmission signal is transmitted by changing the conventional transmission / reception control circuit to the transmission / reception control circuit of the present invention. Terminal 26 (126) to antenna terminal 22
Whereas the transmission loss up to (122) was 1.6 dB in the past, the circuit of the present invention also became 1.6 dB, and the transmission loss from the second transmission terminal 26 (126) to the second reception terminal 25
The isolation up to (125) is 2 in the conventional circuit.
In contrast to 5.4 dB, in the circuit of the present invention, 2 dB
While it is not much different from 5.3 dB, the isolation from the second transmission terminal 26 (126) to the first reception terminal 23 (123) is 24.7 dB in the conventional circuit, In the circuit of the present invention, it is 34.0 dB. Similarly, the isolation from the antenna terminal 22 (122) to the first receiving terminal 23 (123) is 26.7 dB in the conventional circuit, but is improved to 33.6 dB in the circuit of the present invention. .

FIG. 6 shows transmission characteristics from the second transmission terminal 26 (126) to the first reception terminal 23 (123). Note that 0 V is applied to the first control terminal 27 (127),
2.6V was applied to the control terminal 28 (128).

FIG. 6A shows the transmission characteristics of the conventional transmission / reception control circuit, and FIG. 6B shows the transmission characteristics of the circuit of the present invention.

FIG. 7 shows transmission characteristics from the antenna terminal 22 (122) to the first receiving terminal 23 (123).
In addition, 0 V was applied to the first control terminal 27 (127), and 2.6 V was applied to the second control terminal 28 (128).

FIG. 7A shows the transmission characteristics of the conventional transmission / reception control circuit, and FIG. 7B shows the transmission characteristics of the circuit of the present invention.

Further, by changing the conventional transmission / reception control circuit to the transmission / reception control circuit of the present invention, the antenna terminal 22 (122) can be used when receiving the first reception signal when 0V is applied to the first and second control terminals. ) To the first receiving terminal 2
3 (123) from 1.3 dB to 1.4 d
It was not much different from B.

Similarly, at the time of receiving the second reception signal when 0 V is applied to the first and second control terminals, the antenna terminal 22 (122) to the second reception terminal 25 (125)
Pass loss up to 1.5 dB was not changed from 1.5 dB.

[0096]

The transmission / reception control circuit of the present invention is compatible with the dual band, and when transmitting the first transmission signal, the transmission loss of the transmission signal from the transmission terminal to the antenna terminal is small, and the first transmission terminal is connected to the transmission terminal. The isolation between the first transmission terminal and the second reception terminal can be improved while maintaining the isolation between the first reception terminals.

Further, at the time of transmitting the second transmission signal, the transmission loss of the transmission signal from the transmission terminal to the antenna terminal is small, and the second transmission signal is maintained while maintaining the isolation between the second transmission terminal and the second reception terminal. The isolation between the transmitting terminal and the first receiving terminal can be improved.

Further, the transmission loss of the first and second received signals can be kept small.

As described above, while sufficient isolation between the transmitting and receiving terminals and isolation between the antenna terminal and each transmitting and receiving terminal are ensured, there is no increase in loss from each transmitting terminal to the antenna terminal, and the transmission signal is supplied to the transmitting signal. This is a transmission / reception control circuit that does not transmit any noise signal to other terminals.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a transmission / reception control circuit of the present invention.

FIG. 2 is an external perspective view of a coil portion used in a transmission / reception control circuit of the present invention.

FIG. 3 is an exploded perspective view of another circuit board of a coil portion used in the transmission / reception control circuit of the present invention.

4A and 4B are transmission characteristics from a first transmission terminal to a second reception terminal when a transmission / reception control circuit transmits a first transmission signal, and FIG. 4A is a transmission characteristic diagram of a conventional transmission / reception control circuit. (B) is a transmission characteristic diagram of the transmission / reception control circuit of the present invention.

5A and 5B are transmission characteristics of a transmission / reception control circuit from an antenna terminal to a second reception terminal when transmitting a first transmission signal, and FIG. 5A is a transmission characteristic diagram of a conventional transmission / reception control circuit; () Is a transmission characteristic diagram of the transmission and reception control circuit of the present invention.

6A and 6B are transmission characteristics from a second transmission terminal to a first reception terminal when a transmission / reception control circuit transmits a second transmission signal, and FIG. 6A is a transmission characteristic diagram of a conventional transmission / reception control circuit. (B) is a transmission characteristic diagram of the transmission / reception control circuit of the present invention.

FIGS. 7A and 7B are transmission characteristics from an antenna terminal to a first reception terminal when a transmission / reception control circuit transmits a second transmission signal, and FIG. 7A is a transmission characteristic diagram of a conventional transmission / reception control circuit; () Is a transmission characteristic diagram of the transmission and reception control circuit of the present invention.

FIG. 8 is a block diagram of a typical dual band compatible transmission / reception control circuit.

FIG. 9 is a circuit diagram of a conventional transmission / reception control circuit.

[Explanation of symbols]

1, 101, D: Diplexer 3, 103: First transmission line 13, 113: Second transmission line 8, 108: First switch element (PIN diode) 4, 104 .. Second switch elements (PIN diodes) 18, 118... Third switch elements (PIN diodes) 14, 114... Fourth switch elements (PIN diodes) 29. ..Antenna terminals 23, 123 ... first receiving terminals 24, 124 ... first transmitting terminals 25, 125 ... second receiving terminals 26, 126 ... second transmitting terminals 27, 127 ... first control terminal 28, 128 ... second control terminal

Claims (2)

[Claims] A first transmission terminal to which a transmission circuit is connected; a first and second reception terminal to which a reception circuit is connected; a transmission signal limited to a predetermined transmission frequency band; A diplexer for limiting a received signal to a predetermined reception frequency band, a first switch element connected between the first transmission terminal and the diplexer, and a first switch element connected between the first reception terminal and the diplexer. A first transmission line having a line length of λ / 4 of the first transmission signal to be connected, and a first transmission line connected between a first receiving terminal side end of the first transmission line and a ground electrode. 2 switch elements and the second switch element.
A third terminal connected between the transmitting terminal and the diplexer
A second transmission line having a line length of λ / 4 of a second transmission signal connected between the second reception terminal and the diplexer, and a second transmission line of the second transmission line. A fourth switch element connected between the receiving terminal side end of the second and the ground electrode, and first and second control elements for controlling transmission and reception.
, And connected between the first transmission line and the second transmission line via a coil, and when transmitting the first transmission signal, the first, second, and A transmission / reception control circuit, wherein the fourth switch element is turned on, and the second, third, and fourth switch elements are turned on when transmitting the second transmission signal. 2. The transmission / reception control circuit according to claim 1, wherein said coil comprises a meander line pattern or a winding line.