| 摘要 |
<p>PROBLEM TO BE SOLVED: To increase the degree of freedom in design and eliminate the need for an expensive coil for cancelling the pattern capacitance by presetting the impedance of a high frequency device to be mounted to an inductive point from 50Ωby a value equivalent to the pattern capacitance. SOLUTION: The input/output impedance Zin, Zout of a high frequency device is preset to an inductive point a from 50Ωto cancel the pattern capacitance whereby the device has an input/output impedance shifted to 50Ωat point (b) when mounted. If the pattern capacitance is short of 50Ω, the area of the land for soldering the device is increased or inserting capacitors C1, C2 parallel between the device and ground to cancel a pattern capacitance Cp1, Cp2 short of 50Ωsuch as matching circuit of a SAW filter F, thereby matching the impedance to 50Ω.</p> |
