Compact Frequency Reconfigurable UWB Monopole Antenna Loaded with Parasitic Line for Wide Stopband

This paper presents a frequency reconfigurable monopole antenna using a parasitic line which behaves as a half wave-length resonator. The proposed antenna uses a parasitic line near the partial ground plane of the antenna which can control the stopband frequency with the help of two p-i-n diodes. This is a simple technique and can be used with any printed monopole antenna. A truncated elliptical-shaped monopole antenna with a parasitic line is designed for proof of concept. The antenna gives a UWB band (3-10 GHz) when p-i-n diodes are OFF and a sub-6 GHz band (3.2-5.5 GHz) when p-i-n diodes are ON. The antenna is fabricated on FR-4 substrate and measured for its VSWR and radiation characteristics, it exhibits an omnidirectional radiation pattern, and > 70% efficiency and peak realized gains of 3.2 dBi and 2.2 dBi in UWB and sub-6 GHz bands respectively and is suitable for use in UWB and sub-6 GHz wireless systems.