JPS58101501A - High frequency switch device - Google Patents

Abstract

PURPOSE:To obtain a small sized switch device, by forming a diode switch circuit with an arbitrary conduction type of semiconductor chip. CONSTITUTION:Diodes 4, 5 are manufactured in one semiconductor chip in monolithic way. A lambda/4 phase shift circuit line length from a feeding point 14 to a lambda/4 phase shift point 15 has a large shortened rate and is short, because the specific dielectric constant of a silicon semiconductor chip is as large as 11.7. Thus, a diode switch circuit can be made small in size.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to miniaturization of high frequency switching devices.

FIG. 1 is a circuit diagram showing a general high frequency switch device. In the figure, (1) is the transmitter output terminal, (2) is the antenna terminal, (31 is the receiver input terminal, (4) and +51 are diodes, respectively, and +61, +7) and (8) are large printer capacitors. , (9) is a bypass capacitor, Q (I is a high-frequency choke coil, aυ is a resistor that limits the forward current value flowing through the diodes (4) and (51), and a is a resistor that limits the forward current value flowing through the diodes (4) and (51).
) bias power supply terminal, 03 is the λ/4 phase shift circuit line, I is the feed point, a is the feed point 04), λ7'4
Phase shifted λ/4 phase shift point, edge is feeding point Q4 and αS
including the above diodes +4), (51 and λ/
4 This is a diode switch circuit (see the circuit surrounded by the broken line) consisting of the phase shift circuit line a3.

Next, the operation of the high frequency switch device having the above configuration will be explained. First, during transmission, a high positive DC voltage is applied to the power supply terminal 02. Therefore, a direct current forward current limited by the resistance aυ flows through the diodes (41 and (51). At this time, the diodes (4) and (5) have a high frequency resistance of a small value determined by this direct current forward current Therefore, the transmission signal from the transmitter input terminal (11) is connected to the large printer capacitor (6) and the diode (
4) and reach the power supply point α-Xun. At this time, the phase is shifted by υλ/4 from the 9-volt point α above the λ/4 phase shift point, and moreover, it is connected by a diode (51) with low resistance.

Therefore, the impedance Z when looking at the receiver input terminal (3) from the feeding point I is Z=jZotanβ! It can be shown as

Here, Zo is the characteristic impedance of the line, l=λ/4
．． Since it can be shown as β=2π/λ, Z=jZot
anπ/2→oo (anti-resonance), resulting in high impedance. Therefore, most of the transmitted signal can be guided to the antenna terminal (21) via the capacitor (7).

Next, during reception, Ov or a negative DC voltage is applied to the power supply electron α2. At this time, the diode (4) and (
51 operates as a small capacitor.

Then, the received signal induced in the antenna reaches the feeding point I via the antenna terminal (2) and the decoupling capacitor (7). At this time, the impedance when looking from this feeding point I to the transmitter output terminal (1) side is the diode (4
) acts as a small capacitor, it has a high impedance and most of the received signal is guided to the receiver input terminal (3). At this time, diode (5)
Since the diode also operates as a small-capacitance capacitor, the received signal is hardly attenuated by this diode (5).

However, in conventional high-frequency switching devices, the diodes are individual semiconductor elements, and the λ/4 phase shift circuit line is also provided on a glass epoxy substrate, making the device large and making communication equipment more compact. There was a drawback that it could not be done.

Therefore, an object of the present invention is to form a diode switch circuit of a high frequency switch device with one semiconductor chip,
The present invention provides a high frequency switch device that can be miniaturized.

In order to achieve such an object, the present invention includes a first diode whose cathode is connected to the feed point, and a first diode whose cathode is connected to the feed point.
A diode switch circuit consisting of a λ/4 phase shift circuit line connecting the phase shift points and a second diode whose anode connects to the λ/4 phase shift point is formed using a semiconductor chip of any conductivity type. will be described in detail below using examples.

FIG. 2 is a perspective view showing an embodiment in which a diode switch circuit of a high frequency switch device according to the present invention is formed into a semiconductor chip. In the figure, aη is a P-type low resistivity semiconductor substrate, α樟 is a high resistivity N-type layer, 翺 is a high resistivity P-type diffusion region, ■ is a low resistivity N-type diffusion region, and the circle is a high resistivity N-type layer. Low resistivity P-type expansion area, the container is the electrode corresponding to the anode electrode of the diode <41, (to) is the electrode corresponding to the cathode electrode of the diode (4), @ is the electrode corresponding to the cathode electrode of the diode (5)
), a λ/4 phase shift circuit line having an electrode corresponding to the anode electrode of (to) is an electrode corresponding to the cathode electrode (ground electrode) of the diode (51).

Incidentally, it goes without saying that the operation of the diode switch circuit of the high frequency switch device having the above configuration is the same as that shown in Fig. m1.

Next, it will be explained that the high frequency switch device can be miniaturized by the above configuration.

First, the diodes (41 and (5)) can be fabricated monolithically within the same semiconductor chip.Furthermore,
The length of the λ/4 phase shift circuit line from the feed point I to the λ/4 phase shift point must also be shortened by a large reduction rate because the dielectric constant of the silicon semiconductor chip is as high as 11.7. write(
Since the dielectric constant of the glass epoxy substrate is 4.8), the diode switch circuit, which is the main part of the high frequency switch device, can be significantly downsized.

As described above in detail, the high frequency switch device according to the present invention has the effect of being able to significantly downsize the device.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing a general high-frequency switch device, and FIG. 2 is a circuit diagram showing an embodiment in which a diode switch circuit of the high-frequency switch device according to the present invention is made into a semiconductor chip.
It is a congratulatory map. (1)...Transmitter output terminal, (2)...O antenna terminal, (3)...Receiver input terminal, (41 and (5)...Diode, (6+, ( 71 and fil-... decoupling capacitor, (9)...
... / block pass capacitor, shout ... high frequency choke coil, 0υ ... resistance, Q21 ... power supply terminal, OJ ... λ/4 phase shift circuit line, α ... - Feeding point, α9...λ/4 Phase shift point, αO... Diode switch circuit, αη... Semiconductor substrate, or e
...N-type layer, 09...P-type diffusion region, (to)...
・N-type diffusion region, Qυ book...P-type diffusion region, Q2. (
to), t24 and (to)...electrode, (c)...
・λ/4 phase shift circuit line. Note that the same reference numerals indicate the same or equivalent parts. Agent Shin Kuzuno - (1 other person)

Claims (1)

[Claims] In a high-frequency switching device that switches a high-frequency signal between high-frequency terminals, a first diode whose cathode is connected to a feeding point, and a λ/4 diode whose cathode connects to a feeding point and a λ/4 phase shift point.
A high frequency switch device characterized in that a diode switch circuit consisting of a phase shift circuit line and a second diode whose anode is connected to a λ/4 phase shift point is formed using a semiconductor chip of any conductivity type.