High frequency circuits and their measurement methods

Abstract

To provide a high frequency circuit capable of measuring circuit characteristics without influencing the circuit characteristics.SOLUTION: A high frequency circuit includes: an antenna element 1 for receiving a radio signal and output the same; a hybrid coupler 2 for outputting a signal inputted from the antenna element 1 to a first amplifier 3 and a second amplifier 4; the first amplifier 3 for amplifying a signal inputted from the hybrid coupler 2; the second amplifier 4 for amplifying a signal inputted from the hybrid coupler 2; a measurement terminal 5 connected to a terminal serving as an isolation terminal for the terminal to which the antenna element 1 is connected; a phase shifter 6 for adjusting the phase of an output signal of the second amplifier 4; a second hybrid coupler 7 using output of the first amplifier 3 and output of the phase shifter 6 as input; an output terminal 8 to which a signal combined by the second hybrid coupler 7 is outputted; and a second measurement terminal 9 to which a signal combined by the second hybrid coupler 7 is outputted.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a high-frequency circuit that operates in the microwave to terahertz wave bands, and more particularly to an MMIC (Monolithic Microwave Integrated Circuit) that incorporates an antenna. [Background technology]

[0002] Patent Document 1 describes a method in which a movable high-frequency probe and a fixed high-frequency probe of a ground-signal-ground probe connected to both connection terminals of a vector network analyzer are brought into contact with the surface of a conductor pattern formed on a dielectric material to be evaluated, and the frequency characteristics of the complex power ratio are measured by the vector network analyzer while the movable high-frequency probe is moved sequentially, and the relative permittivity of the dielectric material is determined based on the frequency at which the amplitude becomes a minimum value. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7065502 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the method described in Patent Document 1 involves providing multiple ground-signal-ground wiring structures in the middle of the high-frequency circuit, which increases the area of ​​the high-frequency circuit. In addition, the probes are placed on the wiring and antenna within the MMIC, which changes their characteristics and makes it difficult to perform accurate measurements.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a high frequency circuit that allows measurement of circuit characteristics without affecting the circuit characteristics by arranging hybrid circuits at the input and output of the high frequency circuit. [Means for solving the problem]

[0006] The high-frequency circuit of the present invention includes a hybrid circuit that outputs a signal input from an antenna element to a first transistor and a second transistor, and a measurement terminal is connected to a terminal of the hybrid circuit that serves as an isolation terminal relative to the terminal to which the antenna element is connected.

[0007] With this configuration, the measurement terminal is connected to the terminal that serves as the isolation terminal for the terminal to which the antenna element of the hybrid circuit is connected, which allows accurate measurements to be performed without affecting the characteristics of the first and second transistors.

[0008] Furthermore, the high-frequency circuit of the present invention includes a hybrid circuit that outputs a signal input from an antenna element to a first transistor and a second transistor, a measurement terminal connected to a terminal of the hybrid circuit that serves as an isolation terminal with respect to the terminal to which the antenna element is connected, a phase shifter that adjusts the phase of the output signal of the second transistor, a second hybrid circuit that combines and outputs the output signal of the first transistor and the output signal of the phase shifter, an output terminal connected to one terminal from which the output signal of the second hybrid circuit is output, and a second measurement terminal connected to the other terminal from which the output signal of the second hybrid circuit is output.

[0009] With this configuration, the measurement terminal is connected to the terminal that serves as the isolation terminal relative to the terminal to which the antenna element of the hybrid circuit is connected, and the second measurement terminal is connected to the other terminal from which the output signal of the second hybrid circuit is output, making it possible to measure the circuit characteristics without affecting them.

[0010] In addition, in the high-frequency circuit of the present invention, a first termination resistor is arranged to be grounded between the hybrid circuit and the measurement terminal, and a second termination resistor is arranged to be grounded between the second hybrid circuit and the second measurement terminal.

[0011] With this configuration, a first termination resistor is placed between the hybrid circuit and the measurement terminal and a second termination resistor is placed between the second hybrid circuit and the second measurement terminal and is also placed between the hybrid circuit and the second measurement terminal, which reduces the change in impedance when a measurement device is connected to the measurement terminal and the second measurement terminal via a connector or cable, and further reduces the effect of the signal received by the antenna element on the characteristics of the first transistor and the second transistor.

[0012] In the high-frequency circuit of the present invention, a first phase shifter and a first termination resistor are disposed to ground between the hybrid circuit and the measurement terminal, and a second phase shifter and a second termination resistor are disposed to ground between the second hybrid circuit and the second measurement terminal.

[0013] With this configuration, the first phase shifter and first termination resistor are arranged to ground between the hybrid circuit and the measurement terminal, and the second phase shifter and second termination resistor are arranged to ground between the second hybrid circuit and the second measurement terminal. Therefore, when a measurement device is connected to the measurement terminal and the second measurement terminal via a connector or cable, the signal propagating to the first termination resistor and the second termination resistor is reduced, and the signal propagating to the measurement device is increased, enabling accurate measurements.

[0014] In addition, in the high-frequency circuit of the present invention, a first phase shifter is arranged between the hybrid circuit and the measurement terminal, and a second phase shifter is arranged between the second hybrid circuit and the second measurement terminal, and the first phase shifter is arranged between the hybrid circuit and the measurement terminal, and the second phase shifter is arranged between the hybrid circuit and the measurement terminal, and the second phase shifter is arranged between the hybrid circuit and the measurement terminal.

[0015] With this configuration, a first phase shifter is placed between the hybrid circuit and the measurement terminal, and a second phase shifter is placed between the second hybrid circuit and the second measurement terminal, so when a measurement device is connected to the measurement terminal and the second measurement terminal via a connector or cable, the signal transmitted to the measurement device can be increased, enabling accurate measurements.

[0016] Furthermore, a method for measuring a high-frequency circuit of the present invention is a method for measuring a high-frequency circuit including a hybrid circuit that outputs a signal input from an antenna element to a first transistor and a second transistor, in which a measurement terminal is connected to a terminal of the hybrid circuit that serves as an isolation terminal with respect to a terminal to which the antenna element is connected, and a measurement device is connected to the measurement terminal to measure the reflection characteristics of the first transistor and the second transistor.

[0017] With this configuration, the measurement terminal is connected to the terminal that serves as the isolation terminal relative to the terminal to which the antenna element of the hybrid circuit is connected, and a measuring device is connected to the measurement terminal to measure the reflection characteristics of the first transistor and the second transistor, thereby enabling accurate measurements to be performed without affecting the characteristics of the first transistor and the second transistor.

[0018] Furthermore, a method for measuring a high-frequency circuit of the present invention is a method for measuring a high-frequency circuit comprising: a hybrid circuit that outputs a signal input from an antenna element to a first transistor and a second transistor; a phase shifter that adjusts the phase of the output signal of the second transistor; a second hybrid circuit that combines and outputs the output signal of the first transistor and the output signal of the phase shifter; and an output terminal connected to one terminal from which the output signal of the second hybrid circuit is output, wherein a measurement terminal is connected to a terminal of the hybrid circuit that serves as an isolation terminal with respect to the terminal to which the antenna element is connected, a second measurement terminal is connected to the other terminal from which the output signal of the second hybrid circuit is output, and a measuring device is connected between the measurement terminal and the second measurement terminal to measure the pass characteristics of the first transistor and the second transistor.

[0019] With this configuration, the measurement terminal is connected to the terminal that serves as the isolation terminal relative to the terminal to which the antenna element of the hybrid circuit is connected, the second measurement terminal is connected to the other terminal from which the output signal of the second hybrid circuit is output, and a measuring device is connected between the measurement terminal and the second measurement terminal to measure the pass characteristics of the first transistor and the second transistor, thereby making it possible to measure the circuit characteristics without affecting them. [Effects of the Invention]

[0020] The present invention can provide a high frequency circuit that allows measurement of circuit characteristics without affecting the circuit characteristics. [Brief explanation of the drawings]

[0021] [Figure 1] FIG. 1 is a block diagram of a high-frequency circuit according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a block diagram of a high-frequency circuit according to a first alternative aspect of the first embodiment of the present invention. [Figure 3] FIG. 3 is a block diagram of a high-frequency circuit according to a second alternative aspect of the first embodiment of the present invention. [Figure 4] FIG. 4 is a block diagram of a high-frequency circuit according to a third alternative aspect of the first embodiment of the present invention. [Figure 5] FIG. 5 is a block diagram of a high-frequency circuit according to a second embodiment of the present invention. [Figure 6] Figure 6 is a diagram showing the pass characteristics of a high-frequency circuit according to a second embodiment of the present invention, where Figure 6(a) is a diagram showing the pass characteristics from the antenna terminal to the first amplifier and the second amplifier when a measurement device is not connected to the measurement terminal, and Figure 6(b) is a diagram showing the pass characteristics from the antenna terminal to the first amplifier and the second amplifier when a measurement device is connected to the measurement terminal. [Figure 7] FIG. 7 is a diagram showing the pass characteristics from the measurement terminal to the first amplifier and the second amplifier when a measurement device is connected to the measurement terminal of the high-frequency circuit according to the second embodiment of the present invention. [Figure 8]FIG. 8 is a block diagram of a high-frequency circuit according to a first alternative aspect of the second embodiment of the present invention. [Figure 9] Figure 9 is a diagram showing the pass characteristics of a high-frequency circuit relating to a first other aspect of the second embodiment of the present invention, where Figure 9(a) is a diagram showing the pass characteristics from the antenna terminal to the first amplifier and the second amplifier when a measurement device is not connected to the measurement terminal, and Figure 9(b) is a diagram showing the pass characteristics from the antenna terminal to the first amplifier and the second amplifier when a measurement device is connected to the measurement terminal. [Figure 10] FIG. 10 is a diagram showing the pass characteristics from the measurement terminal to the first amplifier and the second amplifier when a measurement device is connected to the measurement terminal of the high-frequency circuit according to the first other aspect of the second embodiment of the present invention. [Figure 11] FIG. 11 is a block diagram of a high-frequency circuit according to a second alternative aspect of the second embodiment of the present invention. [Figure 12] Figure 12 is a diagram showing the pass characteristics of a high-frequency circuit related to a second other aspect of the second embodiment of the present invention, where Figure 12(a) is a diagram showing the pass characteristics from the antenna terminal to the first amplifier and the second amplifier when a measurement device is not connected to the measurement terminal, and Figure 12(b) is a diagram showing the pass characteristics from the antenna terminal to the first amplifier and the second amplifier when a measurement device is connected to the measurement terminal. [Figure 13] FIG. 13 is a diagram showing the pass characteristics from the measurement terminal to the first amplifier and the second amplifier when a measurement device is connected to the measurement terminal of the high-frequency circuit according to the second other aspect of the second embodiment of the present invention. [Figure 14] FIG. 14 is a block diagram of a high-frequency circuit according to a third alternative aspect of the second embodiment of the present invention. [Figure 15] Figure 15 is a diagram showing the pass characteristics of a high-frequency circuit related to a third other aspect of the second embodiment of the present invention, where Figure 15(a) is a diagram showing the pass characteristics from the antenna terminal to the first amplifier and the second amplifier when a measurement device is not connected to the measurement terminal, and Figure 15(b) is a diagram showing the pass characteristics from the antenna terminal to the first amplifier and the second amplifier when a measurement device is connected to the measurement terminal. [Figure 16]FIG. 16 is a diagram showing the pass characteristics from the measurement terminal to the first amplifier and the second amplifier when a measurement device is connected to the measurement terminal of the high-frequency circuit according to the third alternative aspect of the second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, high-frequency circuits according to embodiments of the present invention will be described in detail with reference to the drawings.

[0023] (First embodiment) In FIG. 1, a high-frequency circuit 10 according to a first embodiment of the present invention includes an antenna element 1, a hybrid coupler 2 as a hybrid circuit, a first amplifier 3 as a first transistor, a second amplifier 4 as a second transistor, and a measurement terminal 5. The antenna element 1 receives and outputs a radio signal.

[0024] The hybrid coupler 2 outputs the signal input from the antenna element 1 to the first amplifier 3 and the second amplifier 4. The hybrid coupler 2 outputs a signal that is 90° phase delayed from the signal input from the antenna element 1 to the first amplifier 3. The hybrid coupler 2 outputs a signal that is 180° phase delayed from the signal input from the antenna element 1 to the second amplifier 4. The reflected power from the first amplifier 3 and the second amplifier 4 is combined and output to the measurement terminal 5.

[0025] The first amplifier 3 amplifies the signal input from the hybrid coupler 2 . The second amplifier 4 amplifies the signal input from the hybrid coupler 2 .

[0026] The measurement terminal 5 is a ground-signal-ground terminal that includes a signal terminal 5a connected to the hybrid coupler 2, and a first ground terminal 5b and a second ground terminal 5c connected to the ground of the high-frequency circuit 10.

[0027] In the high-frequency circuit 10 according to the first embodiment configured as described above, a measurement device such as a vector network analyzer can be connected to the measurement terminal 5 to measure the reflection characteristics of the first amplifier 3 and the second amplifier 4.

[0028] Furthermore, since the probes of the measuring device are not placed on the wiring or the antenna element 1, the characteristics of the first amplifier 3 and the second amplifier 4 are not affected, and accurate measurements can be performed.

[0029] As a first alternative aspect of the first embodiment, as shown in FIG. 2, a high-frequency circuit 20 has a termination resistor 21 disposed between the hybrid coupler 2 and the measurement terminal 5 so as to be grounded.

[0030] This reduces the change in impedance when a measurement device is connected to the measurement terminal 5 via a connector or cable, further reducing the impact on the characteristics of the first amplifier 3 and the second amplifier 4.

[0031] 3, in a second alternative aspect of the first embodiment, a high-frequency circuit 30 includes a phase shifter 31 and a termination resistor 32 arranged in a grounded manner between the hybrid coupler 2 and the measurement terminal 5. The phase shifter 31 delays the phase of the signal between the hybrid coupler 2 and the measurement terminal 5 by, for example, 90° and outputs the delayed signal to the termination resistor 32.

[0032] By doing this, when a measuring device is connected to the measuring terminal 5 via a connector or cable, the signal propagating to the termination resistor 32 is reduced and the signal propagating to the measuring device is increased, allowing for accurate measurements.

[0033] 4, in a third alternative aspect of the first embodiment, a high-frequency circuit 40 includes a phase shifter 41 disposed between the hybrid coupler 2 and the measurement terminal 5, and the phase shifter 41 is grounded. The phase shifter 41 delays the phase of the signal between the hybrid coupler 2 and the measurement terminal 5 by, for example, 90°.

[0034] By doing so, when a measuring device is connected to the measuring terminal 5 via a connector or cable, the signal transmitted to the measuring device can be increased, enabling accurate measurements to be made.

[0035] The phase shifter 41 may be connected between the signal terminal 5a of the measurement terminal 5 and the first ground terminal 5b or the second ground terminal 5c.

[0036] (Second embodiment) Next, a second embodiment of the present invention will be described. Since this embodiment partially uses the configuration of the first embodiment, the same components will be assigned the same reference numerals and the characteristic parts will be described.

[0037] In FIG. 5 , a high-frequency circuit 50 according to a second embodiment of the present invention includes a phase shifter 6 that adjusts the phase of the output signal of the second amplifier 4, a second hybrid coupler 7 as a second hybrid circuit to which the outputs of the first amplifier 3 and the phase shifter 6 are input, an output terminal 8 that outputs a signal combined by the second hybrid coupler 7, and a second measurement terminal 9 that outputs the signal combined by the second hybrid coupler 7.

[0038] The phase shifter 6 delays the phase of the output signal of the second amplifier 4 by, for example, 90°. The second measurement terminal 9 is a ground-signal-ground terminal that includes a signal terminal 9a connected to the second hybrid coupler 7, and a first ground terminal 9b and a second ground terminal 9c connected to the ground of the high-frequency circuit 10.

[0039] In the high-frequency circuit 50 according to the second embodiment configured as described above, a signal input to the antenna element 1 is amplified by the first amplifier 3 and the second amplifier 4 and output to the output terminal 8.

[0040] Furthermore, by connecting a measuring device such as a vector network analyzer to the measuring terminal 5 and the second measuring terminal 9, the pass characteristics of the first amplifier 3 and the second amplifier 4 can be measured.

[0041] With this configuration, the measurement terminal 5 serves as an isolation terminal with respect to the antenna terminal to which the antenna element 1 of the hybrid coupler 2 is connected. Therefore, connecting a measurement device to the measurement terminal 5 via a connector or cable has little effect on the characteristics of the signal received by the antenna element 1 being amplified by the first transistor 3 and the second transistor 4.

[0042] Furthermore, when measurements are made by connecting a measuring device to the measuring terminal 5 and the second measuring terminal 9 via a connector or cable, the impedance of the antenna element 1 changes when the measuring member is brought close to the antenna element 1, but the effect on the measurement results is small because there is an isolation relationship between the measuring terminal 5 and the terminal to which the antenna element 1 is connected. Similarly, whether or not a measuring device is connected to the output terminal 8 during measurement also has little effect on the measurement results.

[0043] Various pass characteristics of the high-frequency circuit 50 according to the second embodiment will be described with reference to FIGS.

[0044] FIG. 6( a ) shows the passing characteristics from the antenna terminal to the first amplifier 3 and the second amplifier 4 when the measurement device is not connected to the measurement terminal 5 .

[0045] The pass characteristics from the antenna terminal to the first amplifier 3 (pass characteristics from the antenna terminal to the output terminal 8) and the pass characteristics from the antenna terminal to the second amplifier 4 (pass characteristics from the antenna terminal to the second measurement terminal 9) are uniform and identical from 220 GHz to 330 GHz, and it can be seen that the hybrid coupler 2 has the desired characteristics when no measurement device is connected to the measurement terminal 5.

[0046] FIG. 6(b) shows the passing characteristics from the antenna terminal to the first amplifier 3 and the second amplifier 4 when a measuring device is connected to the measuring terminal 5.

[0047] When a measurement device is connected to measurement terminal 5, the pass characteristics from the antenna terminal to measurement terminal 5 are small, and the signal from the antenna terminal does not propagate to measurement terminal 5. Furthermore, the pass characteristics from the antenna terminal to the first amplifier 3 (pass characteristics from the antenna terminal to output terminal 8) and the pass characteristics from the antenna terminal to the second amplifier 4 (pass characteristics from the antenna terminal to second measurement terminal 9) are uniform and identical from 220 GHz to 330 GHz, which indicates that hybrid coupler 2 has the desired characteristics.

[0048] FIG. 7 shows the pass characteristics from the measurement terminal 5 to the first amplifier 3 and the second amplifier 4 when a measurement device is connected to the measurement terminal 5.

[0049] When a measurement device is connected to the measurement terminal 5, the pass characteristics from the measurement terminal 5 to the first amplifier 3 (pass characteristics from the output terminal 8 to the measurement terminal 5) and the pass characteristics from the measurement terminal 5 to the second amplifier 4 (pass characteristics from the measurement terminal 5 to the second measurement terminal 9) are approximately -5dB to -10dB, and it can be seen that the characteristics of the first amplifier 3 and the second amplifier 4 can be measured at the measurement terminal 5.

[0050] As a first alternative aspect of the second embodiment, as shown in FIG. 8 , a high-frequency circuit 60 has a first termination resistor 61 disposed to ground between the hybrid coupler 2 and the measurement terminal 5, and a second termination resistor 62 disposed to ground between the second hybrid coupler 7 and the second measurement terminal 9.

[0051] This reduces the change in impedance when a measuring device is connected to the measuring terminal 5 and the second measuring terminal 9 via a connector or cable, further reducing the impact on the characteristics of the signal received by the antenna element 1 being amplified by the first amplifier 3 and the second amplifier 4.

[0052] Although the example in which the first terminating resistor 61 and the second terminating resistor 62 are grounded has been shown, a capacitor may be inserted between them and the ground so that only the high frequency components are grounded.

[0053] Various pass characteristics of the high-frequency circuit 60 according to the first alternative aspect of the second embodiment will be described with reference to FIGS.

[0054] FIG. 9( a ) shows the passing characteristics from the antenna terminal to the first amplifier 3 and the second amplifier 4 when the measurement device is not connected to the measurement terminal 5 .

[0055] The pass characteristics from the antenna terminal to the first amplifier 3 (pass characteristics from the antenna terminal to the output terminal 8) and the pass characteristics from the antenna terminal to the second amplifier 4 (pass characteristics from the antenna terminal to the second measurement terminal 9) are uniform and identical from 220 GHz to 330 GHz, and it can be seen that the hybrid coupler 2 has the desired characteristics when no measurement device is connected to the measurement terminal 5.

[0056] FIG. 9(b) shows the passing characteristics from the antenna terminal to the first amplifier 3 and the second amplifier 4 when a measuring device is connected to the measuring terminal 5.

[0057] When a measurement device is connected to measurement terminal 5, the pass characteristics from the antenna terminal to measurement terminal 5 are small, and the signal from the antenna terminal does not propagate to measurement terminal 5. Furthermore, the pass characteristics from the antenna terminal to the first amplifier 3 (pass characteristics from the antenna terminal to output terminal 8) and the pass characteristics from the antenna terminal to the second amplifier 4 (pass characteristics from the antenna terminal to second measurement terminal 9) are uniform and identical from 220 GHz to 330 GHz, which indicates that hybrid coupler 2 has the desired characteristics.

[0058] FIG. 10 shows the pass characteristics from the measurement terminal 5 to the first amplifier 3 and the second amplifier 4 when a measurement device is connected to the measurement terminal 5.

[0059] When a measurement device is connected to the measurement terminal 5, the pass characteristics from the measurement terminal 5 to the first amplifier 3 (pass characteristics from the output terminal 8 to the measurement terminal 5) and the pass characteristics from the measurement terminal 5 to the second amplifier 4 (pass characteristics from the measurement terminal 5 to the second measurement terminal 9) are approximately -5dB to -10dB, and it can be seen that the characteristics of the first amplifier 3 and the second amplifier 4 can be measured at the measurement terminal 5.

[0060] 11 , in a second alternative aspect of the second embodiment, a high-frequency circuit 70 has a first phase shifter 71 and a first termination resistor 72 arranged to ground between the hybrid coupler 2 and the measurement terminal 5, and a second phase shifter 73 and a second termination resistor 74 arranged to ground between the second hybrid coupler 7 and the second measurement terminal 9. The first phase shifter 71 delays the phase of the signal between the hybrid coupler 2 and the measurement terminal 5 by, for example, 90° and outputs the signal to the termination resistor 32. The second phase shifter 73 delays the phase of the signal between the second hybrid coupler 7 and the second measurement terminal 9 by, for example, 90° and outputs the signal to the second termination resistor 74.

[0061] By doing this, when a measuring device is connected to the measuring terminal 5 and the second measuring terminal 9 via a connector or cable, the signal propagating to the first termination resistor 72 and the second termination resistor 74 is reduced, and the signal propagating to the measuring device is increased, allowing for accurate measurements.

[0062] Various pass characteristics of the high-frequency circuit 70 according to the second alternative aspect of the second embodiment will be described with reference to FIGS.

[0063] FIG. 12( a ) shows the passing characteristics from the antenna terminal to the first amplifier 3 and the second amplifier 4 when the measurement device is not connected to the measurement terminal 5 .

[0064] The pass characteristics from the antenna terminal to the first amplifier 3 (pass characteristics from the antenna terminal to the output terminal 8) and the pass characteristics from the antenna terminal to the second amplifier 4 (pass characteristics from the antenna terminal to the second measurement terminal 9) are uniform and identical from 220 GHz to 330 GHz, and it can be seen that the hybrid coupler 2 has the desired characteristics when no measurement device is connected to the measurement terminal 5.

[0065] FIG. 12(b) shows the passing characteristics from the antenna terminal to the first amplifier 3 and the second amplifier 4 when a measuring device is connected to the measuring terminal 5.

[0066] When a measurement device is connected to measurement terminal 5, the pass characteristics from the antenna terminal to measurement terminal 5 are small, and the signal from the antenna terminal does not propagate to measurement terminal 5. Furthermore, the pass characteristics from the antenna terminal to the first amplifier 3 (pass characteristics from the antenna terminal to output terminal 8) and the pass characteristics from the antenna terminal to the second amplifier 4 (pass characteristics from the antenna terminal to second measurement terminal 9) are uniform and identical from 220 GHz to 330 GHz, which indicates that hybrid coupler 2 has the desired characteristics.

[0067] FIG. 13 shows the pass characteristics from the measurement terminal 5 to the first amplifier 3 and the second amplifier 4 when a measurement device is connected to the measurement terminal 5.

[0068] When a measurement device is connected to the measurement terminal 5, the pass characteristics from the measurement terminal 5 to the first amplifier 3 (pass characteristics from the output terminal 8 to the measurement terminal 5) and the pass characteristics from the measurement terminal 5 to the second amplifier 4 (pass characteristics from the measurement terminal 5 to the second measurement terminal 9) are approximately -5dB to -10dB, and it can be seen that the characteristics of the first amplifier 3 and the second amplifier 4 can be measured at the measurement terminal 5.

[0069] 14 , in a third alternative aspect of the second embodiment, a high-frequency circuit 80 has a first phase shifter 81 disposed between the hybrid coupler 2 and the measurement terminal 5 and a second phase shifter 82 disposed between the second hybrid coupler 7 and the second measurement terminal 9 and connected to ground. The first phase shifter 81 delays the phase of the signal between the hybrid coupler 2 and the measurement terminal 5 by, for example, 90°. The second phase shifter 82 delays the phase of the signal between the second hybrid coupler 7 and the second measurement terminal 9 by, for example, 90°.

[0070] By doing this, when a measuring device is connected to the measuring terminal 5 and the second measuring terminal 9 via a connector or cable, the signal transmitted to the measuring device can be increased, allowing for accurate measurements.

[0071] The first phase shifter 81 may be connected between the signal terminal 5a of the measurement terminal 5 and the first ground terminal 5b or the second ground terminal 5c. The second phase shifter 82 may be connected between the signal terminal 9a of the second measurement terminal 9 and the first ground terminal 9b or the second ground terminal 9c.

[0072] Various pass characteristics of the high-frequency circuit 80 according to the third alternative aspect of the second embodiment will be described with reference to FIGS.

[0073] FIG. 15( a ) shows the passing characteristics from the antenna terminal to the first amplifier 3 and the second amplifier 4 when the measurement device is not connected to the measurement terminal 5 .

[0074] The pass characteristics from the antenna terminal to the first amplifier 3 (pass characteristics from the antenna terminal to the output terminal 8) and the pass characteristics from the antenna terminal to the second amplifier 4 (pass characteristics from the antenna terminal to the second measurement terminal 9) are uniform and identical from 220 GHz to 330 GHz, and it can be seen that the hybrid coupler 2 has the desired characteristics when no measurement device is connected to the measurement terminal 5.

[0075] FIG. 15(b) shows the passing characteristics from the antenna terminal to the first amplifier 3 and the second amplifier 4 when a measuring device is connected to the measuring terminal 5.

[0076] When a measurement device is connected to measurement terminal 5, the pass characteristics from the antenna terminal to measurement terminal 5 are small, and the signal from the antenna terminal does not propagate to measurement terminal 5. Furthermore, the pass characteristics from the antenna terminal to the first amplifier 3 (pass characteristics from the antenna terminal to output terminal 8) and the pass characteristics from the antenna terminal to the second amplifier 4 (pass characteristics from the antenna terminal to second measurement terminal 9) are uniform and identical from 220 GHz to 330 GHz, which indicates that hybrid coupler 2 has the desired characteristics.

[0077] FIG. 16 shows the pass characteristics from the measurement terminal 5 to the first amplifier 3 and the second amplifier 4 when a measurement device is connected to the measurement terminal 5. As shown in FIG.

[0078] When a measurement device is connected to the measurement terminal 5, the pass characteristics from the measurement terminal 5 to the first amplifier 3 (pass characteristics from the output terminal 8 to the measurement terminal 5) and the pass characteristics from the measurement terminal 5 to the second amplifier 4 (pass characteristics from the measurement terminal 5 to the second measurement terminal 9) are approximately -5dB to -10dB, and it can be seen that the characteristics of the first amplifier 3 and the second amplifier 4 can be measured at the measurement terminal 5.

[0079] Although the first and second embodiments have been described above as examples in which a branch line coupler is used as the hybrid coupler, a rat race coupler, a Marchand balun, or the like may also be used.

[0080] While an embodiment of the present invention has been disclosed, it will be apparent to one skilled in the art that modifications may be made thereto without departing from the scope of the present invention, and it is intended that all such modifications and equivalents be included in the following claims. [Explanation of symbols]

[0081] 1 antenna element 2 Hybrid coupler (hybrid circuit) 3 First amplifier (first transistor) 4 Second amplifier (second transistor) 5 Measurement terminal 5a signal terminal 5b First ground terminal 5c Second ground terminal 6 Phase shifter 7 Second Hybrid Coupler (Second Hybrid Circuit) 8 output terminals 9 Second measurement terminal 9a Signal terminal 9b First ground terminal 9c Second Ground Terminal 10, 20, 30, 40, 50, 60, 70, 80 High frequency circuit 61 First termination resistor 62 Second termination resistor 71 First Phase Shifter 72 First termination resistor 73 Second Phase Shifter 74 Second Termination Resistor 81 First phase shifter 82 Second Phase Shifter

Claims

1. a hybrid circuit (2) that outputs a signal input from an antenna element (1) to a first transistor (3) and a second transistor (4); A high-frequency circuit in which a measurement terminal is connected to a terminal that serves as an isolation terminal with respect to a terminal to which the antenna element of the hybrid circuit is connected.

2. a hybrid circuit (2) that outputs a signal input from an antenna element (1) to a first transistor (3) and a second transistor (4); a measurement terminal (5) connected to a terminal of the hybrid circuit that serves as an isolation terminal with respect to a terminal to which the antenna element is connected; a phase shifter (6) for adjusting the phase of the output signal of the second transistor; a second hybrid circuit (7) that combines the output signal of the first transistor and the output signal of the phase shifter and outputs the combined signal; an output terminal (8) connected to one terminal from which the output signal of the second hybrid circuit is output; and a second measurement terminal (9) connected to the other terminal from which the output signal of the second hybrid circuit is output.

3. 3. The high-frequency circuit according to claim 2, wherein a first termination resistor (61) is disposed between the hybrid circuit and the measurement terminal in a grounded state, and a second termination resistor (62) is disposed between the second hybrid circuit and the second measurement terminal in a grounded state.

4. 3. The high-frequency circuit according to claim 2, wherein a first phase shifter (71) and a first termination resistor (72) are disposed between the hybrid circuit and the measurement terminal, and a second phase shifter (73) and a second termination resistor (74) are disposed between the second hybrid circuit and the second measurement terminal, and are connected to ground.

5. 3. The high-frequency circuit according to claim 2, wherein a first phase shifter (81) is disposed between the hybrid circuit and the measurement terminal, and a second phase shifter (82) is disposed between the second hybrid circuit and the second measurement terminal, and the first phase shifter (81) is disposed between the hybrid circuit and the measurement terminal, and the second phase shifter (82) is disposed between the hybrid circuit and the measurement terminal, and the second hybrid circuit and the measurement terminal.

6. A method for measuring a high frequency circuit including a hybrid circuit (2) that outputs a signal input from an antenna element (1) to a first transistor (3) and a second transistor (4), comprising: A measurement terminal (5) is connected to a terminal of the hybrid circuit that serves as an isolation terminal relative to a terminal to which the antenna element is connected, A method for measuring a high frequency circuit, comprising connecting a measuring device to the measurement terminal to measure the reflection characteristics of the first transistor and the second transistor.

7. A method for measuring a high frequency circuit comprising: a hybrid circuit (2) that outputs a signal input from an antenna element (1) to a first transistor (3) and a second transistor (4); a phase shifter (6) that adjusts the phase of the output signal of the second transistor; a second hybrid circuit (7) that combines and outputs the output signal of the first transistor and the output signal of the phase shifter; and an output terminal (8) connected to one terminal from which the output signal of the second hybrid circuit is output, A measurement terminal (5) is connected to a terminal of the hybrid circuit that serves as an isolation terminal relative to a terminal to which the antenna element is connected, A second measurement terminal (9) is connected to the other terminal from which the output signal of the second hybrid circuit is output, A method for measuring a high frequency circuit, comprising connecting a measuring device between the measurement terminal and the second measurement terminal to measure the pass characteristics of the first transistor and the second transistor.

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