Improved Boresight Gain in Slotted Trapezoidal Ground UWB Monopole with Non-Concentric Circular Loops

The design and performance analysis of a microstrip-fed circular ring-based planar monopole Ultra Wide-Band (UWB) antennas are investigated in this paper. Three non-concentric circular rings are inserted within the microstrip-fed circular ring monopole antenna backed by reduced ground planes of distinct shapes such as rectangular ground (RG), elliptical ground (EG) and trapezium ground (TG) respectively. The non-concentric rings are scaled optimally, for a comprehensive analysis of their impact on impedance bandwidth and antenna gain in boresight direction. By integrating such structures, the study addresses significant challenges associated with traditional UWB monopole antennas, particularly the degradation of radiation performance at higher frequencies. It is found that non-concentric ring based UWB monopole antenna offers UWB impedance band while demonstrating positive gain in boresight direction up to 8 GHz. Thus, the proposed antenna structures exhibit enhanced UWB impedance bandwidth and improved boresight gain, thereby overcoming the limitations of conventional designs.