ANTENNA IMPEDANCE MATCHING USING NEGATIVE IMPEDANCE CONVERTER AND PRE- AND POST-MATCHING NETWORKS

摘要

There is disclosed a matching network for connecting an electrically small antenna to an RF source or load. The matching network includes a negative impedance converter, a pre-matching network for connecting the negative impedance converter to the antenna and a post-matching network for connecting the negative impedance converter to the RF source or load. The pre-matching network comprises a combination of capacitors and/or inductors to transform both a real part and an imaginary part of an impedance of the antenna. The negative impedance converter is configured to cancel the transformed imaginary part of the impedance of the antenna. The post-matching network comprises a combination of capacitors and/or inductors to transform a residual real part of the impedance of the antenna to match an impedance of the RF source or load. There is also disclosed an antenna system comprising a plurality of antenna radiating elements each having an associated feed, at least one of the feeds being connected to an RF source or load by way of an active matching circuit comprising a pre-matching network, a negative impedance converter and a post-matching network.