Periodic Triangle-Truncated DSPSL-Based Antenna With Backfire to Endfire Beam-Scanning Capacity

A backfire to endfire beam-scanning antenna based on double-side parallel-strip lines (DSPSL) is presented in this communication. The antenna consists of periodic offset DSPSL structures with triangular truncation. A series of uniform DSPSL and offset DSPSL equations were established to analyze its operating modes, transmission mode, and first higher order. The working band range in the periodic DSPSL structure is shown to assist the design of the proposed antenna. The main beam of the antenna scans from backfire to endfire as operating frequency increases owing to its periodic structure. Truncating the periodic offset DSPSL improved the current distribution and consequently broadened the impendence, enhancing the radiation patterns. Experimental results showed that the main lobe scans electronically and continuously from the backfire (-z-direction) to endfire in the yz plane toward the absolute end-firing direction (+z-direction) with two open stopbands when operating frequency increases from 1.2 to 5.9 GHz. The peak gain of the antenna is about 9.7 dBi, and the gain in the whole working band exceeds 4 dBi.