Filter-Bank-Enabled Leaky-Wave Antenna Array Technique for Full-Band-Locked Radar System in Stitched Frequency-Space Domain

Inspired by the filter-bank (FB) concept that is normally used for multi-rate signal processing, an FB-enabled array technique of leaky-wave antennas (LWAs) is proposed and studied for creating full-band-locked frequency-scanning radar (FSR) systems in a stitched frequency-space domain. This is mainly for addressing the coupling dilemma between the range and angle resolutions, which is historically and naturally inherited from a conventional FSR. First of all, the frequency-modulated continuous-wave system architecture is selected to exemplify and recall the characteristics of a conventional FSR with an emphasis on that resolution coupling. Then, a radar solution featuring a stitched frequency-space domain is introduced for the resolution decoupling, depending on an array of FB-enabled LWA channels. With the radar equation, FB-related conditions for realizing the critical frequency-space stitching are analytically derived and equivalently converted into several design specifications of an array of LWAs, i.e., engineered beam-scanning functions, beam-crossovers, and phase alignments. To facilitate the practical implementation of such an array technique, a detailed and generalized design flow is developed. Finally, for a simple proof of concept, an FB-enabled two-channel LWA array is modeled, fabricated, and measured. Simulated and measured results are in a reasonable agreement, and both demonstrate the desired frequency-space stitching behavior, i.e., enhanced spectrum bandwidth and widened radiation beamwidth. The proposed array solution may be potentially deployed for FSR systems with a full-band-locked beam illumination and a decoupled range-angle resolution, which may present a competitor against the phased array technique.