Impedance Matching

Impedance matching is a part of microwave electronics. It is mainly used on transmission lines to achieve the purpose that all high-frequency microwave signals can be transmitted to the load point without any signal reflecting back to the source point, thus improving energy efficiency.

In general, there are two kinds of impedance matching, one is by changing the impedance force, and the other is by adjusting thewavelength of the transmission line.The followings respectively are two kinds of impedance terminal matching methods.

1. Series terminal matching

The theoretical starting point of series terminal matching is to connect a resistance R in series between the signal source end and the transmission line under the condition that the impedance of the signal source end is lower than the characteristic impedance of the transmission line, so as to match the output impedance of the source end with the characteristic impedance of the transmission line,and inhibit the signal reflected from the load end to reflect again.

2. Parallel terminal matching

The theoretical starting point of parallel terminal matching is to match the input impedance of the load end with the characteristic impedance of the transmission line by increasing the parallel resistance in the case of small impedance of the signal source end, so as to eliminate the reflection of the load end.The realization forms are divided into single resistance and double resistance.