A Low-Profile Dual-Polarized Dual-Band Antenna With High Isolation For Drone Application

This paper presents a dual-polarized, dual-band aperture-in-aperture (AIA) antenna for small uncrewed aerial vehicles (UAVs) that combines GNSS/GPS L1-band (viz. 1.568–1.576 GHz) and Ka-band drone-to-satellite links (viz. 29.3–29.70 GHz) in a single, ultra-low-profile package. The radiator fits in a 119.12 mm $\times 119.12$ mm footprint with an overall height of 0.51 mm corresponding to $0.625{\,}\lambda _{0} \times 0.439{\,}\lambda _{0} \times 0.0026{\,}\lambda _{0}$ at the lowest frequency band (L1). The design employs nested apertures, allowing the Ka-band radiator to occupy the center of the L1-band window without blocking it. Concurrent operation is achieved using orthogonal feeds and a via fence-based passive decoupling structure. Additionally, a novel feed via section is introduced at each port of the L-band antenna to enhance intra-band isolation between the Horizontal-polarization (H-pol) and Vertical-polarization (V-pol). Full-wave simulations show $S_{11} \lt -10$ dB across 1.568–1.576 GHz (GNSS L1) and 29.3–29.70 GHz (center frequency at 29.5 GHz). Inter-band isolation exceeds 40 dB, while intra-band port isolation is around 20 dB. The L1 radiator exhibits stable broadside patterns with cross-polarization below −20 dB and a realized gain of around 4.9 dBi. The Ka-band aperture yields a realized gain of 12.4 dBi with dual linear (H/V) polarization for link diversity, where co- and cross-polarization discrimination is better than 20 dB near boresight. The measured results are in close agreement with the simulation results. The AIA approach reduces volume, weight, and cabling compared to separate antennas and simplifies integration on compact airframes.