JPH0795649B2 - RF power combiner - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a high frequency power combiner, and more particularly to a 90 ° hybrid type high frequency power combiner.

[Prior Art] As a combiner (distributor) that distributes or combines high-frequency power according to the purpose, a device formed by a microwave integrated circuit (microwave IC) has been used relatively often. There is. FIG. 3 shows the configuration of the entire high-frequency power amplifier device in the conventional example. The high-frequency input input to the input terminal 50A is distributed to two powers by using the high-frequency power distributor 50, and this is divided into two powers. After being amplified by the amplifiers 51A and 51B, they are combined again by using the high frequency power combiner 52 and output from the output terminal 62B to the load.

In this case, the high frequency power distributor 50 and the high frequency power combiner 52 use the same 90 ° hybrid in principle.
Of these, the high frequency power combiner used as a combiner
52 is configured as shown in FIGS. 4 to 5 (VV sectional view of FIG. 4).

4 to 5, a relatively thin dielectric plate is shown.
The electrodes are placed on both sides of 60 with their central parts facing each other.
61 and 62 are mounted as shown. The performance as a coupler is determined by the overlapping portion of the electrodes 61 and 62. The dimension l of the overlapping portion of the central portion is determined by l = (2n + 1) · λ _g / 4, where n = 0,1,2, ... λ _g : wavelength of the used frequency.

Ground plates 63 and 64 are provided facing both surfaces of the dielectric plate 60 and at predetermined intervals. Reference numeral 65 indicates a power absorption resistor. In the case of FIG. 4, the output side end of the electrode 61 is connected to the ground plate 64 via the power absorption resistor 65.

In the high frequency power combiner 52 of FIG. 4, the transfer coefficient amplitudes of the path from the input terminal 62A to the output terminal 62B and the path from the input terminal 61A to the output 62B are set to be equal. In addition, each of these paths has a mutual transfer coefficient.
It is set to have a phase difference of 90 °.

The high frequency power combiner 52 shown in FIGS. 4 to 5 is incorporated as shown in FIG.
When powers having the same output level of A and 51B and a phase difference of 90 ° between the pressures are input, the combined output thereof appears at the output end 62B.

In this case, when the output conditions from the power amplifiers 51A and 51B collapse, the combined output appearing at the output end decreases, and the reduced power is absorbed by the power absorption resistor 65 described above. The adverse effect of reflection is prevented in advance.

[Problems to be solved by the invention]

However, in such a conventional example, when the two-man power to be combined is different from the ideal state due to a failure of the power amplifier or the like, excessive power flows into the power absorption resistor 65. Therefore, especially when synthesizing high power, the power absorption resistance
There were inconveniences such as 65 burnout accidents, possibly leading to burnout accidents of the entire power amplifier.

[Object of the Invention]

The present invention improves the inconvenience of the conventional example, detects an abnormality of two electric powers to be combined immediately and with high accuracy, and controls the switch circuit provided in the input stage of the high-frequency distributor to open, thereby reducing the power consumption. It is an object of the present invention to provide a high-frequency power combiner capable of preventing a burnout accident of an absorption resistor and improving the durability of the entire device.

[Means for solving problems]

Therefore, in the present invention, a 90 ° hybrid that has two input ends on one side and a single output end on the other side, and is equipped with a power absorption resistor on a part of the output end side. Type high frequency power combiner, an abnormal voltage detecting means is connected in parallel to the power absorption resistor, and a comparator is provided for comparing an output value of the abnormal voltage detecting means with a preset reference value. It is intended to achieve the above-mentioned object by adopting a configuration in which the switch circuit of the high frequency input stage is controlled to be opened by the output of the above.

Example of Invention

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. Here, the same reference numerals are used for the same constituent members as those in the conventional example described above.

In FIG. 1, 1 is a high frequency excitation circuit and 2 is a switch circuit. The output of the high-frequency excitation circuit 1 is sent to the high-frequency power distributor 50 via the switch circuit 2, is divided into two parts here, and is amplified specifically by the power amplifiers 51A and 51B, and then to the high-frequency power combiner 52. It is being sent. Here, the high-frequency power distributor 50 and the high-frequency power combiner 52 are of the same 90 ° hybrid type in principle as in the above-described conventional example. The abnormal voltage detection means 3 is provided side by side with the power absorption resistor 65 provided on the output side of the high frequency power combiner 52.

This abnormal voltage detecting means 3 is provided with a resistor 3A and a series circuit of a detector 3B as shown in the example of FIG. As the resistor 3A, one having a resistance value sufficiently larger than the characteristic impedance of the high frequency power combiner 52 is used. Further, in FIG. 2, 3C indicates a DC return choke coil, and 3D indicates a bypass capacitor. The DC return choke coil 3C and the bypass capacitor 3D do not necessarily have to be provided. In this case, for the resistor 3A portion, a small capacity capacitor may be used instead of this resistor. 3E indicates a signal output terminal.

The output of the abnormal voltage detecting means 3 is sent to the comparator 4. A reference signal of a constant level is constantly input to the comparator 4 from the reference level setting circuit 5. The comparator 4 is
When the output of the abnormal voltage detecting means 3 exceeds the reference value, the control signal S for controlling the opening of the switching circuit 2 at the high frequency input stage can be immediately output. in this case,
The switch circuit 2 has such a structure that once it is "disconnected", it does not become "contact" again unless it is operated from the outside. Other configurations are the same as those of the conventional example described above.

Next, the overall operation of the above embodiment will be described.

First, the resistor (or capacitor) of the abnormal voltage detection means 3
Since the impedance of 3A is set to a value higher than the characteristic impedance of the high-frequency power combiner as described above, even if it is connected to the power absorption resistor 65, there is no effect on the overall power combining action. It does not cause the inconvenience.

Two inputs for combination are added to the input terminals 61A and 62A. When each of these inputs is deviated from the ideal state, a voltage is generated across the power absorption resistor 65 as described above. This voltage is detected by the above-mentioned resistor (or capacitor) 3A, detected by the detection circuit formed by the detector 3B, the choke coil 3C and the bypass capacitor 3D, and appears as a DC signal at the signal output terminal 3E.

Thus, when two inputs to be combined are deviated from the ideal state and at least one of an amplitude error and a phase error occurs, an abnormal voltage is generated in the power absorption resistor 65,
It is effectively detected by the abnormal voltage detection means 3, and the switch circuit 2 is opened via the comparator 4 based on this detection signal as described above.

Therefore, in the present embodiment, at the same time as the occurrence of an abnormality, each operation of power distribution, amplification, and combination is immediately stopped, thereby releasing the overload state of the power absorption resistor 65 and causing a burnout accident of the entire device. Effectively prevented.

In the above embodiment, for convenience of description, an example in which the coupling type strip line is used as the 90 ° hybrid has been described, but the same means can be used for other 90 ° hybrids. .

〔The invention's effect〕

Since the present invention is configured and functions as described above, according to this, it is possible to effectively prevent the burnout accident of the power absorption resistor of the power combiner using the 90 ° hybrid type when an abnormality occurs, and Since the switch circuit can be controlled to open by the action, damage can be prevented from reaching other parts other than the power absorption resistor, which can significantly increase the durability of the entire device. It is possible to provide an excellent high-frequency power combiner that does not exist.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a circuit diagram showing a high frequency power combiner portion in FIG. 1, and FIGS. 3 to 4 are explanatory views showing conventional examples, respectively. Figure 5 is the fourth
It is sectional drawing which followed the VV line of a figure. 2 ... Switch circuit, 3 ... Abnormal voltage detection means, 4 ...
Comparator, 52A ... single output end, 61A, 62A ... two input ends, 65 ... power absorption resistor.

Claims (1)

[Claims] 1. A 90 ° hybrid type having two input ends on one side and a single output end on the other side, and a part of the output end side is equipped with a power absorption resistor. In the high frequency power combiner, the power absorption resistor is connected in parallel with the abnormal voltage detecting means, and a comparator for comparing the output value of the abnormal voltage detecting means with a preset reference value is provided. A high-frequency power combiner characterized by controlling the opening of the switch circuit at the high-frequency input stage by the output.