JPH0241009A - Hyb reflecting type phase device - Google Patents

Abstract

PURPOSE:To increase the variable phase quantity by applying a reverse bias voltage to a varactor element so as to vary the junction capacitance. CONSTITUTION:A high frequency signal inputted from an input port 1 is divided into a coupling port 3 and a passing port 4 by a 90.3dB hybrid 8. Then the signals are reflected in varactor diodes (D) 7a, 7b respectively and combined by the 90.3dB hybrid 8 again and outputted from an isolation port 2. In this case, a reverse bias voltage is applied to the diodes D 7a, 7b to change the capacitance of the D 7a, 7b thereby shifting the phase. Moreover, inductances 6a, 6b are placed in series to increase the phase change.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a HYB reflection type phase shifter using a distributed constant circuit, and in particular, by applying a reverse bias voltage to the variable capacitance element, This invention relates to a HYB reflective phase shifter that utilizes changes in junction capacitance.

[Prior Art] As a conventional HYB reflection type phase shifter, there is one as shown in Fig. 4. 8 in Fig.
@3dB hybrid, this 90°3dB hybrid 8 consists of an input port 1, an isolation port 2, a car 2 pulling port 3, and a passing port 4. The coupling port 3 and the passage port 4 are connected to small capacitance varactor diodes 7a and 7b, one end of which is connected to the ground 9.
5 in the figure is a bias circuit consisting of a resistor.

One end of each of the coupling port 3 and passing port 4 of the 90° 3 dB hybrid 8 and paractor diodes 7a and 7b serving as respective grounded variable capacitance elements.
is connected by an extremely short wire with negligible inductance. Note that when using a beam type variable capacitance element, wires are not required and are attached to one end of each of the coupling port 3 and passage port 4 to the AND side of the beam lead, and the other cathode side is attached to the ground plane. When the impedance changes of the varactor diodes 7a and 7b are shown on the Smith chart shown in FIG. 2, points A and B show the impedance of the varactor diodes 7a and 7b when a reverse voltage is applied to the varactor diodes 7a and 7b. There is a range of variation.

Letting the capacitances at points A and B be C^ and CB, respectively, the impedance at each point is: To explain the operation of this conventional example, a high frequency signal input from input port 1 is coupled by a 90" 3 dB hybrid 8. It is divided into a port 3 and a pass port 4, reflected by the radiator diodes 7a and 7b, and combined again by the 90"3 dBz/bright 8 and output from the isolation port 2. At this time, a reverse bias voltage is applied to the varactor diodes 7a, 7b, and the junction capacitance, ltC, of the varactor diodes 7a, 7b is changed to change the phase of the output.

[Problems to be solved] In the conventional HYB reflection phase shifter described above, the phase can only be changed by changing the capacitance of a variable capacitance element such as a varactor diode, so there is a problem that the variable phase amount is small. .

The present invention has been made in view of the above-mentioned problems.
The object of the present invention is to provide a HYB reflective phase shifter that increases the amount of variable phase by applying a reverse bias voltage to a variable capacitance element to change the junction capacitance.

[Means for Solving the Problems] In order to solve the drawback of small variable capacitance, the present invention provides a 90'3dB hybrid configured with a distributed constant circuit with an input port and an isolation vibration port as input terminals, and a 90'3dB hybrid as described above. In a HYB reflection type phaser configured with a variable capacitance element connected between one end of each of a coupling boat and a passage port and the ground, the geometric mean value of the minimum reactance and maximum reactance of the capacitance value of the variable capacitance element is calculated. The variable capacitance element is made higher than the line impedance, and a wire whose inductance value is selected to approximately resonate with the minimum reactance of the capacitance element is connected in series to the variable capacitance element to increase the variable phase amount.

[Example] Next, an example of the present invention will be described with reference to the drawings.

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

The gO'3dB hybrid 8 is composed of an input port 1, an isolation port 2, a cup 1 non-port 3, and a passing port 4. Small lactator diodes 7a and 7b are attached to the lactator diodes 7a and 7b, respectively.
Hereinafter, inductances 6a and 6b) are connected.

Further, a bias circuit 5 consisting of a resistor is provided.

Next, the operation of the above embodiment will be explained. The high frequency signal input from input capo) 1 is 903dB hybrid 8
is divided into a coupling port 3 and a passing port 4, and is reflected by varactor diodes 7a and 7b, respectively.
Combined again with 903dB hybrid 8, isolation port? It is output from At this time, by applying a reverse bias voltage to the varactor diodes 7a and 7b and changing the junction capacitance cj of the varactor diodes, the phase is shifted by the output.

If the impedance change of only the varactor diode with respect to the capacitance change is compared on a Smith chart with and without the inductance L, the results are as shown in FIG.

Points A and B are the change range of the impedance of the varactor diode when a reverse voltage is applied to the varactor diode, and C and D are the inductances 6a and 6 in series.
This is the range of change in impedance when b is added. A
The capacitance at point, B point, 0 point, and D point are respectively C^* CB
+ cc l co, inductance 6a, 6b
If the series inductance of is L, the impedance at each point is.

Therefore, if inductances 6a and 6b are inserted in series,
On the Smith chart, the impedance changes by ωL, so the amount of phase change increases accordingly.

Here, as shown in Fig. 3, when the capacitance variation range of a single varactor diode is at the frequency used and the reverse bias voltage Ov, it is in region A or region B, and the junction capacitance NCjT4^X with the maximum power supply used is In this case, if you choose a varactor diode with a small capacitance like the one in region A, you can change the impedance to the inductive region depending on the size of the inductance L, so you can make the phase amount larger than the conventional phase shifter. is possible.

[Effects of the Invention] As explained above, according to the present invention, by inserting a wire serving as an inductance in series with the variable capacitance element,
The effect is that even if the same varactor diode as before is used, the amount of phase change can be larger than that of the conventional one, and a phase shifter that can have a large phase change can be constructed using only varactor diodes without having to choose a varactor diode that has a wide capacitance change range. There is.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of an embodiment of the present invention, FIG. 2 is a Smith chart showing the impedance change range of a varactor diode, and FIG. 3 is a diagram showing the junction capacitance Cjo and A Smith chart diagram showing the conditions for CJM^X, and FIG. 4 is a circuit diagram of a conventional HYB reflective phase shifter. ! : Input port 2: Input port 3: Coupling port 4: Passing port 5: Bias circuit 6a, 6b: Inductance 7a, 7b: Varactor diode 8: 90" 3dB hybrid 9

Claims (1)

[Claims] a 90° 3 dB hybrid configured with a distributed constant circuit with input ports and isolation ports as input terminals, and a variable capacitance element connected between one end of each of the coupling port and the passing port of the 90° 3 dB hybrid and the ground; A HYB reflection type phase shifter comprising: a wire having an inductance value that approximately resonates with a minimum reactance of the variable capacitance element is connected in series to the variable capacitance element.