Bandwidth Enhancement of the Millimeter-Wave Microstrip Linear Array With Loading of Shorting Pins

A broadband, series-fed, millimeter-wave (MMW) microstrip linear array is investigated. This array is evolved from a stub-loaded microstrip line, which has two resonant modes in the passband and an impedance bandwidth of about 26%. By simply inserting three pairs of shorting pins at the two ends of the microstrip line to regulate the field/current distributions, four additional resonances can be excited, significantly increasing the operating bandwidth to 63.5%. In addition, the original gain dips caused by anti-phase (equivalent) magnetic current disappear and the gain becomes quite stable, showing the maximum value of 12.82 dBi and a 3 dB bandwidth of 53.8%. Also, the first sidelobe level (FSLL) is lower than -10 dB from 26.6 to 44.2 GHz (49.7%) and lower than -20 dB from 26.6 to 30.7 GHz (14.3%). Therefore, the proposed array features great advantages, such as a simple structure and an enhanced bandwidth with good sidelobe suppression.

Automated summary

A broadband, series-fed, millimeter-wave microstrip linear array is studied. By inserting three pairs of shorting pins at the two ends of the microstrip line, additional resonances are excited, significantly increasing the operating bandwidth. The proposed array has advantages such as a simple structure, enhanced bandwidth, and good sidelobe suppression.