%0 Journal Article
%T Design and Investigation of Broadband Monopole Antenna Loaded with Non-Foster Circuit
%A Fei-Fei Zhang
%A Bao-Hua Sun
%A Xiaohui Li
%A Wei Wang
%A Jin-Yuan Xue
%J PIER    C
%D 2010
%I EMW Publishing
%R 10.2528/PIERC10081609
%X The possibility of using non-Foster circuit to expand the bandwidth of a monopole antenna is investigated theoretically. Beginning with an inductor-loaded monopole antenna resonating at different frequencies by changing the value of the loaded inductor, we show that a frequency-dependent inductor is needed to enhance the bandwidth of the monopole antenna. The curve for the reactance of the frequency-dependent inductor versus frequency is fitted, which enlightens us to use a non-Foster reactive circuit to realize the frequency-dependent inductor. Based on the above studies, a monople antenna loaded with a non-Foster circuit is presented. Simulated results demonstrate that the input reactance of the loaded antenna becomes stable and approaches zero, which favors the impedance matching and extends the bandwidth to a certain extent. Finally, a passive (Foster) matching circuit is designed to improve the bandwidth further. A 0.69-m monopole antenna with 2.0:1 VSWR in the frequency range 30--150 MHz is designed and investigated.
%U http://www.jpier.org/pierc/pier.php?paper=10081609