Formulation and Analysis of Shorted U-Shaped Microstrip Antenna for Broadband Dual Frequency Response

A U-shaped quarter wave microstrip antenna with two uneven arms and shorting wall meant for broad-band dual frequency response was reported. Antenna fabricated on FR4 substrate was fed electromagnetically using another patch on the same layer with different shapes. For getting broad impedance bandwidth at lower band at 900MHz, U-shaped patch with uneven arms was fabricated at height of 5mm, 7.5mm and 11mm. The measured bandwidth observed respectively at those three substrate heights were 7%, 10% and 18%. For getting broad bandwidth at both the bands modifications were done in coaxially fed patch, resulted into dual frequency operations at 900MHz and 1800MHz with impedance bandwidth of 13.3% and 20%. In contrast, a vibrant portrayal for resonance modes of reported structures that results in dual frequency broadband operation is not given in the reported work. In the offered work paper, an exploration clarifying dual frequency broad-band response for one of the reported configurations is presented using surface current distributions and resonance plots. Supplementary formulation in resonant length at two staggered modes at lower frequency band in shorted U- shaped patch is also proposed. Thus, suggested work gives comprehension into the running of shorted U-shaped antenna.