Current Issue
Efficient information acquisition with minimal resource expenditure is a central goal of modern sensor technologies. While conventional radar systems for high-resolution angle estimation typically rely on complex multi-channel architectures, the targeted use of frequency-dependent antenna characteristics opens new possibilities for simplifying system architectures. The present study follows the approach of realizing
simultaneous range and angle estimation using a single-channel frequency-modulated continuous wave radar operating at 60 GHz. This is achieved by employing leaky-wave antennas with frequency-dependent beam steering, where the main lobe continuously scans with the transmit frequency, enabling angular resolution. Two additively manufactured antennas are implemented and realized for this purpose. The first is
a slow-wave leaky-wave antenna, achieving a beam steering range of ±21° over the frequency band from 55 GHz to 65 GHz,exhibiting a gain of 9.5 dBi and a linear beam angle-to-frequency relationship. The second antenna features a serpentine design with a wider total beam steering range of approximately ±38° in the frequency range from 58 GHz to 63.5 GHz and a gain between 10 dBi and 13 dBi. The overall system realized with the serpentine antenna achieves an angular resolution of up to 8° as well as a range resolution of approximately 30 cm. The antenna structures are fabricated using high-resolution stereolithography 3-D printing and subsequently silver-coated, enabling cost-effective, mechanically precise, and low-loss antenna realization in the millimeter-wave regime. The beam directions vary with frequency, thus allowing angular resolution over the evaluated received frequency band. By employing two ports with opposing squint characteristics, a larger angular coverage can be achieved. This configuration results in a virtual bandwidth extension that improves both angular and range resolution. The overall system is based on a commercially available, highly integrated radar chip. The developed antenna enables angle estimation with only a single receive channel. The connection is established via a specially designed waveguide transition from a patch structure to a rectangular waveguide, which is mechanically modular, simulation-optimized, and precisely realized through additive manufacturing. For signal evaluation, a segmented signal processing scheme is used that analyzes both the range and angle of the reflected signals. The resulting association between target reflection and antenna beam angle enables two-dimensional localization. Extensive measurements characterize the entire system and its components. One multi-target measurement with varying reflector positions confirms the suitability for simultaneous range and angle estimation using only one channel. The transition, signal processing, and antennas have been successfully validated. The presented concept offers a promising approach to reduce system complexity in millimeter-wave radar systems while enabling high angular resolution. Mapping directional information onto the frequency axis constitutes an alternative encoding of the spatial dimension, which not only allows hardware savings but also opens new design opportunities for frequency-selective radiating antennas.
ISBN: 978-3-948749-62-0
DOI: https://doi.org/10.24352/ub.ovgu-2026-024
