Tunable Multi-Band Microstrip Antenna Based on Artificial Magnetic Conductor

The use of artificial magnetic conductor (AMC) on microstrip antenna design allows the dimension of antenna to be more compact so that it is beneficial for the use in portable communication devices. Apart from its small size, the microstrip antenna can generate multiple frequency response which is more cost effective due to its suitability for several applications which have appropriate frequency specifications. In this paper, an AMC-based tunable multi-band microstrip antenna is designed by incorporating external components, namely varactor diode, into the AMC structure. The incorporation of varactor diodes with varied reverse DC bias voltages can affect the capacitance value on the antenna. Two layers of 1.6 mm thick FR4 Epoxy dielectric substrate are used for designing the antenna with the dimension of 51 mm × 51 mm × 3.2 mm. The characterization results show that the proposed microstrip antenna could produce tunable multi-band frequency response in the frequency range of 1.575 GHz to 2.595 GHz along with the reverse DC bias voltage variation. The higher the applied reverse DC bias voltage across the varactor diode, the smaller the capacitance value yielding the higher the resonant frequency.