Author(s)
Nathan Golding, Nainesh Lad, Kevin Hernandez, Isaiah Pisani, Ryan VanZalen, Stephanie Torres, Alex McDonald, William Van Atten V, Nicolas Renaud, Laila Marzall, and Zoya Popovic
Abstract
Hybrid electronically scanned phased arrays offer the flexibility to support multiple simultaneous signals, spatial filtering, and interference suppression through beam steering and nulling. These capabilities make them an adequate architecture for spectrum sharing and coexistence research in realistic field settings. The University of Colorado Microwave Research Group, in collaboration with SpectrumX Flagship1, has formed a multidisciplinary team of electrical, mechanical, and computer engineering students to design and implement a portable phased array demonstrator. The demonstrator consists of a 16-channel hybrid phased array with data converters operating in a high-frequency baseband (2.7–3.7 GHz) and frequency translation boards to extend operation to 7.0–8.4 GHz. The system integrates into a rugged, water-resistant Pelican Case with an operating temperature range of –10° to 50°C, supporting aperture-level simultaneous transmission and reception in field environments. Among the main design challenges addressed are antenna topology, thermal management, frequency planning, translation board design, power distribution, and compact mechanical integration. The platform achieves the minimum technical requirements to enable meaningful coexistence experiments for SpectrumX: 160 MHz instantaneous bandwidth per signal, two simultaneous signals in transmit/receive (LTE and radar chirp), 10 W minimum EIRP, 22 dBi broadside antenna gain, ±40° beam steering free of grating lobes, and ≤100 W total power consumption. The system further supports advanced beamforming features, including phase and power calibration procedures, an assisted beacon beamforming routine, programmable nulling, and beam tapering (windowing). A user interface enables selection of modulation schemes, power levels, manual progressive phase shifts, and tapering functions, while ensuring signal distortion remains compliant with 3GPP standards. Safety and usability are reinforced with a dedicated stop button and robust monitoring functions. The phased array demonstrator is designed as a versatile platform for field-deployable spectrum coexistence experiments, enabling researchers to explore next-generation spectrum sharing strategies. Future work will refine performance metrics, including P1dB, EVM, ACPR, NF, and LO leakage, to ensure compliance with both experimental needs and wireless communication standards.