| 摘要 |
PURPOSE:To improve a control characteristic and a high frequency characteristic by placing an FET like a distributed constant, and controlling it by the same condition. CONSTITUTION:An internal electric conductor 3 is formed in the shape of a comb in a prescribed section, and its uneven amount is set to the maximum in the center of the comb-shaped part. An earth electric conductor 10 which forms an inter-digital constitution with the comb-shaped part of the electric conductor 3 and also is connected with a ground electric conductor 2 by a through-hole electric conductor 8 is formed. The uneven part of the electric conductor 3 and the uneven part of the electric conductor 10 constitute a drain electrode 5 of an FET 4 and a source electrode 6 of the FET4, respectively, and a gate electrode 7 of the FET 4 consisting of a bend structure is formed in the inter-digital constitution formed by the electric conductors 3, 10. In this way, since the FET4 like a distributed constant is formed by one electrode 7, the variable attenuation is controlled simply and easily. Also, inductance and capacitance generated by the electrodes 5, 6, or the influence by them are also reduced, and a good characteristic is obtained. |
