Low-Cost Frequency-Scanning Shared-Aperture Antenna Based on Reflectarray and Leaky-Wave Antenna

A novel shared-aperture antenna, composed of a Ku-band linear-polarized leaky-wave antenna (LWA) and a Ka-band linear-polarized reflectarray antenna (RA), is proposed in this letter. The Ku-band LWA and Ka-band RA with high-gain and low-cost characteristics are employed to achieve frequency-scanning capability. To achieve a shared-aperture design, the Ka-band RA is placed above the Ku-band LWA. Meanwhile, the copper-clad plane of the Ku-band LWA serves as the ground of the Ka-band RA. Additionally, the position of the Ku-band slot and the size of the Ka-band patch are elaborately designed to avoid the influence of the Ka-band patch on the Ku-band LWA. A prototype is fabricated and measured, verifying the frequency-scanning capability in both Ku- and Ka-bands. Moreover, the Ku-band peak gain is 21.2 dBi at 16.3 GHz, corresponding to an aperture efficiency of 52%, and the Ka-band peak gain is 24.6 dBi at 28.7 GHz, corresponding to an aperture efficiency of 36%. Within the 3 dB beam scanning gain loss, the Ku-band LWA achieves a scanning range of −13°∼−54° in 15.1–16.9 GHz and the Ka-band RA achieves a scanning range of −2°∼−12° in 26.5–32 GHz. The measured results are in reasonable agreement with the simulated results.