Linear Tapered Slot Antenna (LTSA) is an attractive candidate as a radiating element in frequency scanning arrays. LTSA element backed by a rectangular cavity had been investigated and is proven to posses various physical design parameters suitable to optimize its performance. This study is focused on the feed position variation to optimize the performance while maximum of the current density variation is maintained in the slot region. It was observed that if the stub base of the microstrip feed structure is located in the middle of the slot region, current maximum can be obtained within the slot region at the expense of smaller return loss, contrary to the previously obtained optimization where the base of the stub was on the side of the slot line region.
Furthermore, if the rectangular cavity is replaced by a circular cavity, then there is a slight increase in the bandwidth and a small drop in the return loss. When two LISA elements are placed back to back and excitation is achieved via strip line, rather than a single element microstrip excitation, circular cavity backed radiating elements could be tuned to obtain higher return loss. The strip line excitation also caused the decrease in the bandwidth. The mode structure excited in the circular cavity has to be studied further as well as its effects of the resonance frequency of the LTSA
