| 摘要 |
PROBLEM TO BE SOLVED: To protect an ultra high frequency circuit in a semi-millimetric wave band and a millimetric wave band from a static electricity surge. SOLUTION: In this static electricity protecting method, one ends (point A and point B) of microstrip lines L2, L3 ofλ/4 in length which are connected with the input end and the output end of a circuit 10 to be protected are connected with a power source and ground through diodes CR1, CR2 and diodes CR3, CR4, respectively. These diodes are connected in the inverse polarity of DC. Accordingly, the points A and B are connected through capacitors C2 and C3 in high frequencies. The stray capacitances of the diodes CR1-CR4 are connected in parallel with the capacitors C2, C3 in high frequencies, so that influence is little. The microstrip lines ofλ/4 long have high impedance in high frequencies, so that the circuit 10 to be protected is scarcely affected by the diode connection. On the other hand, surge is absorbed by the diodes and the circuit 10 is protected.
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