JPH0531362U - High frequency signal switch - Google Patents

Abstract

(57) [Abstract] [Purpose] To widen the applicable frequency range of high frequency signals by reducing the effect of the intrinsic capacitance of the pin diode of the high frequency signal switch using the pin diode. [Configuration] A series resonance circuit 2 of inductors L ₁ and C ₁ having a resonance frequency of the frequency of a used high frequency signal is provided between an output side terminal of a pin diode 1 inserted in a high frequency signal path and ground, and an intermediate connection point thereof. A switching circuit 3 for inserting / short-circuiting the high resistance R ₁ is provided between the bias power supply and the bias power supply, and the high resistance R ₁ is short-circuited / inserted in response to the bias power supply on / off, and the bias power supply is turned off to generate a high frequency When the signal is turned off, the extremely small resonance resistance of the series resonance circuit 2 serves as a load for the pin diode.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a high frequency signal switch used for communication equipment and using a PIN diode.

[0002]

[Prior Art]

 Conventionally, as the high frequency signal switch, the on / off ratio is obtained only by changing the series resistance of the PIN diode with respect to the high frequency.

[0003]

[Problems to be solved by the device]

 However, since there is a coupling between input and output due to the capacitance between the terminals of the PIN diode, a sufficient on / off ratio of the resistance value, that is, the current attenuation ratio by the PIN diode cannot be obtained, so it is practically used as a switch in the GHz band. There is an upper problem.

An object of the present invention is to solve the problem of input / output coupling due to the capacitance between the terminals of the PIN diode in the related art and to obtain a high on / off ratio (attenuation ratio) for a high frequency signal. To provide a container.

[0005]

[Means of the Invention for Solving the Problems]

 The high-frequency signal switch of the present invention has a PIN diode connected in series between an input terminal and an output terminal of a high-frequency input signal, and turns on / off a DC bias current flowing through the PIN diode to generate a high-frequency signal at the output terminal. A high-frequency signal switch for turning on / off an output signal, comprising: a series resonance circuit of an inductor and a capacitor, which is connected between an output side terminal of the PIN diode and ground, and has a frequency of the high-frequency input signal as a resonance frequency. A switching circuit that is connected between an intermediate connection point between the inductor and the capacitor of the series resonance circuit and the bias power supply and inserts / short-circuits a high resistance, and simultaneously turns on / off the DC bias current flowing through the PIN diode. It is characterized in that the high resistance of the switching circuit is configured to be short-circuited / inserted.

[0006]

【Example】

 FIG. 1 is a circuit configuration diagram showing an embodiment of the present invention. In the figure, 1 is a PIN diode (CR₁), And the resistance value for high-frequency signals changes due to the DC bias current. 2 is a series resonance circuit, which is an inductor L having a series resonance frequency substantially equal to the frequency of the high frequency signal.₁And capacitor C ₁ Consists of. Reference numeral 3 is a switching circuit, and the capacitor C of the series resonant circuit 2 is turned on when the PIN diode 1 is turned on and when it is turned off.₁Parallel resistance R₁The damping ratio as a switch is switched by switching the short circuit / insertion and changing Q.

Next, the operation of the high frequency signal switch of the present invention will be described in detail below with reference to the equivalent circuit of FIG. In FIG. 2, C ₂ is a capacitance between the terminals of the PIN diode 1, and S ₂ is a switch which is an element which models the ON / OFF operation of the PIN diode 1. R ₂ represents the resistance value of the PIN diode 1 to a high frequency signal when it is off, and the equivalent circuit of the PIN diode 1 is represented by 1.

In the figure, when the high frequency output signal is in the ON state, the switch S ₁ is connected to the a side and the switch S ₂ is connected to the c side, and the capacitor C ₁ of the series resonance circuit 2 has an extremely small power source impedance R. _{Since 4} is connected in parallel and the load of the PIN diode 1 becomes the inductor L ₁ , the loss of the switch becomes the minimum state. In the OFF state, the switch S ₁ is connected to the b side and the switch S ₂ is connected to the d side. At this time, since the value of R ₂ is very large, the PIN diode 1 becomes almost equivalent to the electrostatic capacitance C ₂ between terminals, and Q of the resonance circuit consisting of the inductor L ₁ and the capacitor C ₁ is connected in parallel with C _1. Since the resistance component is the sum of R ₁ and R ₄ , the resistance component is large, and the resonance resistance is extremely small, so that the damping of the switch is large.

FIG. 3 is a schematic circuit diagram of a high frequency signal switch according to the present invention. When turned on, an on signal is input by the on / off signal, the transistor Q ₁ is turned on, a direct current flows through the FET Q ₂ and the PIN diode CR ₁ , the FE TQ ₂ is amplified with a constant gain, and the PIN diode CR ₁ Has almost zero loss, and the resonance circuit has a characteristic with only a flat inductor L ₁ having very small Q and almost no influence of the resonance circuit because the switch S ₁ is connected to a. The frequency characteristic at this time is shown in FIG.

At the time of off, the on / off signal becomes an off signal, the transistor Q ₁ is turned off, a direct current does not flow through the PIN diode CR ₁ , the FET Q ₂ is attenuated, and the resonance circuit has a switch S ₁ b By connecting to, the Q becomes large, and the resonance resistance with an extremely small resonance point becomes the load resistance of the PIN diode, so the attenuation as a switch becomes large. The frequency characteristic at this time is shown in FIG. Since there is a resonance point near the frequency (1 GHz) of the required high frequency signal, an on / off ratio of about 70 dB can be obtained compared to when it is on.

[0011]

[Effect of the device]

 As described in detail above, according to the present invention, the ON / OFF ratio of the high frequency signal can be set to a large value with the circuit configuration in which the resonance circuit and the Q switching circuit thereof are added, which is a great advantage as a switch for the high frequency signal. is there.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention.

FIG. 2 is an equivalent circuit diagram of FIG.

FIG. 3 is a specific circuit diagram of the present invention.

FIG. 4 is a frequency characteristic when the present invention is on / off.

[Explanation of symbols]

 1 PIN diode 2 Series resonance circuit 3 Switching circuit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mikio Takano 2-3-13 Toranomon, Minato-ku, Tokyo Kokusai Electric Co., Ltd.

Claims (1)

[Scope of utility model registration request] 1. A PIN diode is connected in series between an input terminal and an output terminal of a high frequency input signal, and a high frequency output signal appearing at the output terminal is turned on by turning on / off a DC bias current flowing through the PIN diode. A high-frequency signal switch that turns on / off, a series resonance circuit of an inductor and a capacitor connected between the output side terminal of the PIN diode and the ground and having a frequency of the high-frequency input signal as a resonance frequency, and the series resonance circuit. And a switching circuit that is connected between an intermediate connection point between the inductor and the capacitor and a bias power supply and inserts / short-circuits a high resistance, and simultaneously turns on / off the DC bias current flowing through the PIN diode, and simultaneously increases the high resistance of the switching circuit. A high-frequency signal switch characterized by being configured to short-circuit / insert.