A single-control tuning circuit for electrically small antennas

It is often desirable to tune electrically small antennas at their feed terminals. An "L" matching circuit for this purpose is considered. It is shown that one fixed element and one variable tuning element are adequate for certain small antennas. The manner in which losses affect the circuit effiiciency and the single-control tuning feature is discussed. Application of the technique to a tunable cavity antenna is noted.