JPH0211161B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a microwave circuit, particularly a monitor circuit that monitors and detects an input signal using a microwave directional coupler.

Conventionally, there are circuits shown in FIG. 1 and FIG. 2, respectively, for monitoring and detecting microwave input signals.

In the conventional microwave input signal monitor circuit shown in FIG. 6 represents a termination resistor.

With such a circuit configuration, when a microwave signal is applied to the terminal 1, a monitor signal of the microwave input signal coupled by the directional coupler 5 is outputted to the terminal 3.

Next, FIG. 2 shows a conventional microwave signal detection circuit. In this circuit, 5 is a microwave directional coupler, 1 is an input terminal, 2 is an output terminal, 3 is a coupling terminal for terminal 1, 4 is an isolation terminal for terminal 1, and 6 is a termination element (in this example, a resistor ). 7 is a detection diode (for example, a shot key barrier diode), 8 is a bypass circuit (in this example, a capacitor), and 9 is a detection output terminal.

With such a circuit configuration, when a microwave signal is applied to terminal 1, a microwave signal coupled by directional coupler 5 appears at terminal 3, and this is further transmitted by detection diode 7 and capacitor 8. The signal is detected. As the detection diode 7, for example, a Schottky barrier diode or the like is used, which has a small inter-terminal capacitance and extremely short turn-on and turn-off times. Therefore, a detected signal of the microwave signal input to the terminal 1 is outputted to the terminal 9.

Conventionally, a circuit for monitoring and detecting a microwave input signal has two separate circuits: the monitor circuit shown in Figure 1 and the detection circuit shown in Figure 2, so the frequency of the microwave signal is several GHz. In this case, two microwave directional couplers occupy most of the mounting area.

SUMMARY OF THE INVENTION An object of the present invention is to provide a microwave monitor circuit that monitors and detects microwave signals and is miniaturized by using a single microwave directional coupler.

Embodiments of the present invention will be described below with reference to the drawings.

Referring to FIG. 3, the microwave monitor circuit according to the first embodiment of the present invention has an input terminal 1, an output terminal 2, a coupling terminal 3 for the terminal 1, and an isolation terminal 4 for the terminal 1 in the microwave direction. a terminating element (in this example, a resistor) 6 having one end connected to the isolation terminal 4 and the other end connected to the coupling terminal 3, and a detection output terminal having one end connected to the coupling terminal 3 and the other end thereof. A detection diode (for example, a shot key barrier type diode) 7 that detects the microwave signal connected to the detection output terminal 9 and a short-circuit surface for the microwave signal whose one end is connected to the detection output terminal 9 and the other end is grounded. Isolation for isolating a bypass circuit (in this example, a capacitor) 8 and a detection output terminal 9 and a monitor output terminal 11, one end of which is connected to the coupling terminal 3 and the other end of which is connected to the microwave monitor output terminal 11. A circuit (an attenuator in this example) 10 is included.

With such a circuit configuration, when a microwave signal is applied to terminal 1, a microwave signal coupled by directional coupler 5 appears at terminal 3, and on the other hand, this signal passes through attenuator 10 and becomes a microwave signal. The signal is guided to a wave monitor output terminal 11, and the other side is detected by a detection diode 7 and a capacitor 8. Since the bypass circuit 8 is a circuit for creating a short circuit for microwave signals, this circuit may be a distributed constant bypass circuit. Therefore, when a microwave signal is applied to the terminal 1, a branched microwave signal is output to the microwave monitor output terminal 11, and is used as a monitor output of the input signal. Further, a DC signal obtained by detecting the same microwave signal by the detection diode 7 is outputted to the detection output terminal 9, and this terminal can be used as a monitor of the transmission output power or as an alarm signal. The microwave monitor output terminal and the detection output terminal are isolated by an attenuator 10, so that the detection output signal of the detection output terminal 9 is not affected by the termination condition of the microwave monitor output terminal 11.

Next, FIG. 4 shows a configuration diagram of a microwave monitor circuit according to a second embodiment of the present invention. In this embodiment, when compared with the configuration diagram shown in FIG. 3, the polarity of the detection diode 7 is reversed, and the isolation circuit (attenuator) 10 in FIG. 3 is replaced by another isolation circuit ( In this example, the configuration uses an impedance converter (12) having a passage loss, but this configuration can also obtain the same effect as the present invention.
Further, in FIG. 4, an impedance matching element (for example, a resistor or a distributed circuit) may be provided in series with the detection diode 7.

According to the present invention, as explained above, the microwave signal monitor and detection circuit can be configured by one microwave directional coupler, thereby achieving advantages such as cost reduction and miniaturization.

[Brief explanation of drawings]

1 and 2 are block diagrams showing a conventional microwave signal monitor circuit and a detection circuit, and FIGS. 3 and 4 are block diagrams of a microwave monitor circuit according to an embodiment of the present invention. 1... Input terminal, 2... Output terminal, 3... Coupling terminal, 4... Isolation terminal, 5... Microwave directional coupler, 6... Termination element (for example, resistor), 7... Detection diode (for example, shot key barrier diode), 8... bypass circuit (for example, capacitor), 9... detection output terminal, 10... isolation circuit (for example, attenuator), 11... monitor output terminal, 12...Isolation circuit (for example, impedance converter).

Claims (1)

[Claims] 1. A directional coupler having an input terminal, an output terminal, a coupling terminal, and an isolation terminal; a terminating element having one end connected to the isolation terminal and the other end grounded; A detection diode for detecting a microwave signal connected to the coupling terminal and the other end connected to the detection output terminal, and a short-circuit surface for the microwave signal having one end connected to the detection output terminal and the other end grounded. A microwave monitor configured by a bypass circuit and an isolation circuit that isolates the detection output terminal and the monitor output terminal, one end of which is connected to the coupling terminal and the other end of which is connected to the monitor output terminal. circuit. 2. The microwave monitor circuit according to claim 1, wherein the isolation circuit is comprised of an attenuator. 3. The microwave monitor circuit according to claim 1, wherein the isolation circuit is comprised of an impedance converter with a passing loss.