An application of the negative impedance converter to resistively loaded vee dipole antenna matching

A negative impedance converter (NIC) is applied to resistively loaded vee dipole (RVD) antenna matching. The RVD antenna based on the Wu-King loading profile has large reflection at the feed point because the antenna impedance has high resistance and large negative reactance at low frequencies. To effectively reduce the reflection at low frequencies, the NIC based on operational amplifiers (op-amps) is employed for impedance matching. The matching network is designed such that the RVD antenna is matched to a 75 ohm feeding transmission line. The stability of the network is investigated based on the transient responses obtained from a circuit simulator. The reflection performance of the impedance-matched RVD antenna is measured and shown that the NIC-based matching network improves the impedance matching of the RVD antenna at low frequencies.