Lai, Cheng-KaiCheng-KaiLaiShen, Chun-HungChun-HungShenWu, Yi-YoYi-YoWuLin, Yi-ChengYi-ChengLin2026-04-242026-04-242025-12-0815223965https://www.scopus.com/record/display.uri?eid=2-s2.0-105030832669&origin=resultslisthttps://scholars.lib.ntu.edu.tw/handle/123456789/737507This article presents a systematic design methodology for X-type Composite Right/Left Handed (CRLH) unit cells and their application in leaky wave antennas (LWA). Through extraction and analysis of LWA parameters including propagation constants and Bloch impedance from the unit cell's scattering parameters, we establish critical performance indicators. The proposed approach is validated through implementation of a compact LWA consisting of 15 cascaded unit cells. The antenna demonstrates excellent impedance matching with a worst case of -15 dB return loss over the simulated frequency within 4.0 to 9.0 GHz. In additional, the antenna achieves full-space scanning capability from 4.8 GHz to 8.2 GHz (± 90 degrees). The design effectively addresses previous limitations in scanning range and the asymmetric scanning distribution while maintaining a compact size of only 2.5 λ0 at the center frequency of 6 GHz.falseconference paper10.1109/ap-s/cnc-usnc-ursi55537.2025.112667582-s2.0-105030832669