Feedline Design for a Series-Fed Binomial Microstrip Antenna Array With No Sidelobes

In this letter, a novel feedline configuration is proposed to eliminate the sidelobes by controlling the current distribution. This is achieved by adjusting the widths of the feedline of a series-fed microstrip antenna array. Even-odd mode analysis is provided to understand the effect of the feedline widths on current distribution. A binomial series-fed five-element microstrip antenna array is designed with the proposed feedline. The designed microstrip series-fed binomial array has no sidelobes in the radiation pattern with a realized gain of 11.1 dBi at the resonance frequency with 80% efficiency. It has a cross-polar level of 40 dB and a front-to-back ratio of 20 dB. A prototype of the proposed design has been realized. The simulated and measured results are in good agreement.