JPS60119131A - High frequency switching device - Google Patents

Abstract

PURPOSE:To make a switch contactless and to obtain a small-sized high frequency switching device by arranging four terminals for input/output and constituting a high frequency signal switching part between these terminals by the combination of diodes and phase circuits. CONSTITUTION:When the 1st bias circuit 9 is turned on by the 1st bias switching circuit 40 and a forward DC current is made to flow into the 1st and 2nd pin diodes 13, 14, these pin diodes 13, 14 act as fine high frequency resistors determined by the forward Dc current. If the length from a connection point 17 to a connection point 19 is lambda/4 when the wavelength is defined as lambda, impedance observed from the connection point 17 to the 2nd terminal 22 is high impedance because the connection point 19 shifted by lambda/4 phase is earthed through the 2nd pin diode 14 which is the fine high frequency resistor. Consequently, a high frequency signal reaching a connection point 18 is guided to the 4th terminal 24 through the 4th decoupling capacitor 11.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a high frequency switching device, and particularly to a high frequency switching device suitable for antenna switching.

[Prior Art] FIG. 1 is a diagram showing an example of a high frequency switch device for antenna switching of a radio device using a conventional diversity reception method. In the figure, a changeover switch 80 is connected to a first input terminal 1 and an output terminal 2. Further, the changeover switch 70 is connected to the second input terminal 3 and the input/output terminal 4. Common contact 8 of changeover switch 80 is connected to common contact 7 of changeover switch 70 . The electromagnetic relay 6 switches the common contact 8, and the electromagnetic relay 5 switches the common contact 7. A transmitter is connected to the first input terminal 1, a receiver is connected to the output terminal 2, and an antenna is connected to the second input terminal 3 and input/output terminal 4, respectively.

Next, the operation of opening the antenna switching high frequency switch will be explained. When the electromagnetic relay 6 is turned on, the common contact 8 is connected to the first input terminal 1 side. Further 'ai
When the m-type relay 5 is turned off, the common contact 7 is connected to the input/output terminal 4 side. In this state, when a high frequency signal from the transmitter is applied to the first input terminal 1, the high frequency signal is guided from the input/output terminal 4 to the antenna.

Next, when the electromagnetic relay 6 is turned off, the common contact 8 is connected to the output terminal 2 side. Furthermore, when the electromagnetic relay 5 is turned off, the common contact 7 is connected to the input/output terminal 4 side.

In this state, the high frequency signal from the antenna is guided from the input/output terminal 4 to the receiver connected to the output terminal 2.

Next, when the electromagnetic relay 6 is turned off, the common contact 8 is connected to the output terminal 2 side. Further, when the electromagnetic relay 5 is turned on, the common contact 7 is connected to the second input terminal 3 side. In that state, the high frequency signal from the antenna is guided from the second input terminal 3 to the receiver connected to the output terminal 2.

Although the high-frequency switch device for antenna switching performs the above-described operation, the high-frequency signal switch section is a mechanical contact, so chattering is likely to occur, and the device is also large in size.

SUMMARY OF THE INVENTION The present invention has been made to improve these drawbacks, and therefore, the main object of the present invention is to provide a high-frequency switch device that has a contactless switch and is miniaturized.

To summarize the present invention, it is a high frequency switching device in which four input/output terminals are provided and a high frequency signal switch section between these terminals is constructed by combining a diode and a phase circuit.

The above objects and other objects and features of the present invention will become more apparent from the following detailed description with reference to the drawings.

[Embodiments of the invention] FIG. 2 is a diagram showing an embodiment of the present invention.

In the figure, the first terminal 21 is connected to the anode of the first pin diode 13 via the first decoupling capacitor 100, and the cathode thereof is connected to one end of the first impedance element 31. First impedance element 3
1 has direct current conductivity and its length is a certain value. The impedance of impedance element 31 changes depending on its length.

The other end of the first impedance element 31 is connected to the second terminal 22 via the second decoupling capacitor 101. The first terminal 21, the first decoupling capacitor 100, the first ρin diode 13, the first impedance element 31, the second decoupling capacitor 101, and the second terminal 22 constitute a first series circuit. .

The anode of the second PIO diode 1' 14 is connected to the connection point 19 between the first impedance element 31 and the second decoupling capacitor 101, and its cathode is grounded.

One end of the first bias circuit 9 is connected to the anode of the first pin diode 13, and the other end is grounded. A first bias switching circuit 40 is connected to the first bias circuit 9 . When the first bias switching circuit 40 turns on the first bias circuit 9, the first bias circuit 9
is the first p1n diode 13. A positive forward bias voltage is applied to the second piO diode 14, and the first p1n diode 1 is applied via the first impedance element 31.
3° Direct current is passed through the second pin diode 14 in the forward direction. When the first bias circuit 9 is switched off by the first bias switching circuit 40, the first bias circuit 9 is switched off by the first p1n diode 13. No bias voltage is applied to the second PIN diode 14, and the first PIN diode 13. No forward direct current flows through the second pin diode 14. The third terminal 23 is connected to the third pin diode 15 via the third decoupling capacitor 110.
, and its cathode is connected to one end of the second impedance element 32. The second impedance element 32 has DC conductivity and has a given length.

The impedance of the impedance element 32 changes depending on its length. The other end of the second impedance element 32 is connected to the fourth terminal 24 via a fourth decoupling capacitor 111.

Third terminal 23 and third decoupling capacitor 11
0, the third PIN diode 15, the second impedance element 32, the fourth decoupling capacitor 111, and the fourth terminal 24 constitute a second series circuit. The anode of the fourth PIN diode 16 is connected to the connection point 20 between the second impedance element 32 and the fourth decoupling capacitor 111, and its cathode is grounded. One end of the second bias circuit 10 is connected to the anode of the third pin diode 15, and the other end is grounded. A second bias switching circuit 41 is connected to the second bias circuit 10 .

When the second bias switching circuit 41 switches on the second bias circuit 10, the second bias circuit 10 switches between the third pin diode 15° and the fourth p+n diode A-.
A forward bias voltage is applied to the third pin diode 16 through the second impedance element 32.
5. A forward direct current is passed through the fourth pin diode 16. When the second bias switching circuit 41 switches off the second bias circuit 10, the second bias circuit 1
0 is the third pin diode 15. No bias voltage is applied to the fourth PLL diode 16, and the third PLL diode 15. No forward direct current flows through the fourth pin diode 16. The connection point 17 between the first piO diode 13 and the first impedance element 31 and the third p
A fifth decoupling capacitor 12 is connected between a connection point 18 between the 1n diode 15 and the second impedance element 32 .

Next, the operation of the embodiment shown in FIG. 2 will be explained.

The first bias switching circuit 40 switches on the first bias circuit 9, and the first p1n die A-do 13, the second p1n die A-do
When a forward direct current is passed through the pin diode 14,
These p1n diodes operate as minute high-frequency resistances determined by forward direct current. Now, the high frequency signal applied to the first terminal 21 is transmitted to the first decoupling capacitor 100, the first p1 which is a minute high frequency resistor.
0 diode 13 and reaches the connection point 17. If the length from connection point 17 to connection point 19 is, for example, λ/4, where λ is the wavelength of the high-frequency signal used, connection point 19 with a phase shift of λ/4 is a minute high-frequency resistance. Since the second pin diode 14 is grounded, the impedance Z seen from the connection point 17 to the second terminal 22 is expressed as Z-jZo tan BfL - (1). Here, 70 is the characteristic impedance of the line made of impedance elements having DC conductivity, and β is the phase coefficient. Now, since it is expressed as −λ/4°β−2π/λ, equation (1) is Z = , +Zo tan 7C
/2-”-(2), from the connection point 17 to the second
The impedance when looking at the terminal 22 is high impedance. Therefore, the high frequency signal passes through the fifth decoupling capacitor 12 and reaches the connection point 1. At this time, if the second bias circuit 10 is switched off by the second bias switching circuit 41, the third pin diode 15. No forward direct current flows through the fourth PIN diode 16, and these PLN diodes have minute capacitance, resulting in high impedance. Therefore, the high frequency signal that has reached the connection point 18 is guided to the fourth terminal 24 through the fourth decoupling capacitor 111.

Next, the second bias switching circuit 41 switches on the second bias circuit 10, and the third p1n diode 1
5. When forward direct current is passed through the fourth pln diodes 16, these p1n diodes operate as minute high-frequency resistances determined by the forward direct current. The high-frequency signal now applied to the second terminal 23 reaches the connection point 18 through the third p1n diode 15, which is a small high-frequency resistor.

If the length from the connection point 18 to the connection point 20 is, for example, 2/4, where the wavelength of the high-frequency signal used is λ, then from equations (1) and (2), the length from the connection point 18 to the fourth The impedance when looking at the terminal 24 becomes high impedance. Therefore, the high frequency signal passes through the fifth decoupling capacitor 12 and reaches the connection point 17. At this time, the first bias switching circuit 40 switches the first bias circuit 9
is switched off, the first p1n diode 13. No forward direct current flows through the second p1n diodes 14, and these p1n diodes have minute capacitance, resulting in high impedance. Therefore, the high frequency signal that has reached the connection point 17 is guided to the second terminal 22 through the second large ring capacitor 101.

Next, the first bias switching circuit 40 and the second bias switching circuit 41 switch between the first bias circuit 9 and the second bias switching circuit 40 and the second bias switching circuit 41.
The bias circuits '10 of the first p
in diode 13. When forward direct current is passed through the second atn diode 14, third pln diode 15, and fourth p1n diode 16, these pin diodes act as minute high-frequency resistances determined by the forward direct current 11. Operate. Also, from connection point 17 to connection point 1
9, and assuming that the length from connection point 18 to connection point 20 is, for example, λ/4, respectively, where the wavelength of the high frequency signal used is λ, then equations (1) and (2) are obtained. Therefore, the impedance seen from the connection point 17 to the second terminal 22 and the impedance seen from the connection point 18 to the fourth terminal 24 are both high impedances. Therefore, now
The high frequency signal applied to the first terminal 21 is connected to the first decoupling capacitor 100. Connection point 17. Second decoupling capacitor 12. Connection point 18. It is led to the third terminal 23 through the third decoupling capacitor 110.

Next, the first bias switching circuit 40 and the second bias switching circuit 41 switch between the first bias circuit 9 and the second bias switching circuit 40 and the second bias switching circuit 41.
When both the bias circuits 10 of the first p1n diodes 13 . A second pin diode 14 and a third p1n diode 15. No forward direct current flows through the fourth pin diode 16, and these p1
The n-diode has a small capacitance and therefore has a high impedance. Therefore, the high frequency signal now applied to the fourth terminal 24 is transmitted to the fourth decoupling capacitor 11'I, the connection point 18. Fifth decoupling capacitor 12. It is conducted to the second terminal 22 through the decoupling capacitor 101 at the connection point 17.12.

In addition, in the embodiment described above, the case where the 0111 diode is grounded at a connection point whose phase is shifted by length - λ/4 is explained, but the phase is changed by the length history where equation (1) becomes high impedance. The same effect as in the above embodiment can be obtained even when the pin diode is grounded at the connection point - which is shifted.

Furthermore, the combination of grounding the p1n diodes at the connection points shifted in phase by the length U of the above embodiment may be used alone or in series, and the same effect as in the above embodiment can be obtained.

In addition, in the above embodiment, a case was explained in which a high frequency switch device was constructed by applying a positive bias voltage to the pll-diode or not applying a bias voltage to the pll-diode.
The same effects as in the above embodiment can be obtained even when a pn diode is used instead of the i r+ diode and a positive or negative bias voltage is applied to it to construct a high frequency switch device.

In addition, by configuring this high frequency switch device on a J7 film substrate, Y-tube components can be used, and if a thick film substrate material with a high dielectric constant is used as the surrounding material, the wavelength shortening rate is large, so the phase part The length of the line can be shortened.

[Effects of the Invention] As described above, according to the present invention, by configuring the high frequency switch section by combining a diode and a phase circuit,
The switch can be made contactless, and the high frequency switch device can be downsized.

[Brief explanation of the drawing]

The first factor is a diagram illustrating an example of a conventional high frequency switch device for switching an air conditioner. FIG. 2 is a diagram showing an embodiment of the present invention. In the figure, 9 is the first bias circuit, 10 is the second bias circuit, 100 is the first decoupling capacitor, 101 is the second decoupling capacitor, 110 is the third decoupling capacitor, and 111 is the fourth decoupling capacitor. , 12 is the fifth decoupling capacitor, 13 is the first pin diode, 14 is the second
15 is the third pin diode,
16 is the fourth pin diode, 17.18.19.2
0 is the connection point, 21 is the first terminal, 22 is the second terminal, 2
3 is a third terminal, 24 is a fourth terminal, 31 is a first impedance element, 32 is a second impedance element, 4
0 is a first bias switching circuit, and 41 is a second bias switching circuit. Agent Masuo Oiwa

Claims (3)

[Claims] (1) Between the first terminal and the second terminal, the first
a first series circuit in which a capacitor, a first diode, a first impedance element having DC conductivity and a predetermined impedance, and a second capacitor are connected in series in the stated order; a second diode connected between the connection point of the impedance element and the second capacitor and a ground point and in the same direction as the first diode; a first bias circuit that sequentially applies a bias voltage via an impedance element and variably applies the bias voltage so as to selectively make the first and second diodes conductive and non-conductive; Between the third terminal and the fourth terminal, a third capacitor, a third diode, a second impedance element having DC conductivity and a predetermined impedance, and a fourth capacitor are provided. the second connected in series in the order
a fourth diode connected between a connection point of the second impedance element and the fourth capacitor and a ground point and in the same direction as the third diode; A bias voltage is applied in conjunction with the fourth diode through the second impedance element, and the bias voltage is variably applied so as to selectively make the third and fourth diodes conductive and non-conductive. a fifth capacitor connected between a connection point between the first diode and the first impedance element, and a connection point between the third diode and the second impedance element; A high frequency switching device consisting of (2) The high frequency switch device according to claim 1, wherein the first, second, third and fourth diodes are pin diodes. (3) The high frequency switch device according to claim 1, wherein the high frequency switch device is configured on a substrate.