Theory, design and validation of a tunable, injection-matched, 2-port antenna

The wideband frequency tunability of a two-port microstrip-fed patch antenna is achieved using injection matching. It is demonstrated that controlling the relative amplitude and phase shift between the excitation signals at port one and port two of the microstrip-fed patch antenna can tune its operating band to a lower wideband frequency range compared to the fundamental intrinsic resonance frequency of the corresponding one-port antenna. The resulting two-port antenna has an overall simulated efficiency in excess of 80% with fairly stable radiation pattern in the E-plane. The antenna is suitable for use in wireless communication applications in the C-band.