| 摘要 |
PROBLEM TO BE SOLVED: To provide a high-frequency circuit with a small power loss. SOLUTION: Two PIN diodes 130a and 130b divided in prescribed size are formed on a semiconductor substrate. Then, a coplanar line composed of a signal line 110 and a ground line 120 which are provided in parallel with each other is formed, and the PIN diodes 130a and 130b are arranged under the signal line 110 at both its sides so that they are bilateraly symmetrical. With this setup, a coupling capacitance produced between the signal line 110 and the lowermost N-type GaAs layers 131a and 131b of the PIN diodes 130a and 130b and ground wirings 134a and 134b connected to them is reduced to an irreducible minimum. Therefore, a high-frequency switching circuit having a small power loss can be realized. The PIN diodes 130a and 130b are prescribed in size (impedance) and formed bilateraly symmetrical, so that electromagnetic wave distribution is not disturbed in the signal line 110. Therefore, a high-frequency switching circuit of superior in isolation characteristics can be obtained.
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