Institute of Communications and Connected Systems


Electronically Steerable Parasitic Array Radiator (ESPAR) transceiver

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Examples of antenna array, with a background of a computer generated waveform.

6 July 2018

Developing and testing a pre-commercialisation prototype of an Electronically Steerable Parasitic Array Radiator (ESPAR) transceiver

Funder EPSRC
Amount 96 000 GBP (total)

Project website https://epsrc.ukri.org/

Research theme logos - Intelligent High Capacity Networks, Ubiquitous Connectivity, Infrastructures for Smart Services and Applications
Research topics Electronically Steerable Parasitic Antenna Arrays | Multiple Input Multiple Output | IoT Devices


Massive MIMO arrays are envisaged for 5G and beyond deployment due to the colossal gains in spectral efficiency. Existing implementations, however, involve tens of RF chains to support massive MIMO transmission, and hence a prohibitive hardware complexity.

Several photographs of antenna designs, next to a pen for scale, the antenna arrays are approximately 1/4 the length of the pen.
Electronically Steerable Parasitic Antenna Radiator (EPSAR) technology enables the diversity and spectral efficiency gains of massive MIMO techniques by use of hybrid analogue-digital techniques and load controlled radiators. Accordingly, with respect to the state-of-the-art, ESPAR offers orders of magnitude gains in hardware- , cost-, space-, and power-efficiency.

Since the gain in spectrum efficiency from massive MIMO deployment translates into increased capacity, a mobile operator which for instance has 20 million subscribers could support an additional 5 million subscribers using ESPAR-based massive MIMO deployment without additional spectrum costs, hence increasing profit margins.

The benefits of ESPAR transmission extend beyond massive MIMO, and they can find benefits in hardware-/power-efficient access points, deployment in drone communications, and other yet-to-be-explored applications.


  • A. Li, C. Masouros, and M. Sellathurai, “Analog-Digital Beamforming in the MU-MISO Downlink by use of Tunable Antenna Loads”, IEEE Trans. Veh. Tech., vol. 67, no. 4, pp. 3114-3129, April 2018 DOI: 10.1109/TVT.2017.2776563
  • A. Li, C. Masouros, and C. B. Papadias, “MIMO Transmission for Single-fed ESPAR with Quantized Loads”, IEEE Trans. Comms., vol. 65, no. 7, pp. 2863-2876, July 2017, DOI: 10.1109/TCOMM.2017.2692224
  • C. Masouros, M. Sellathurai, T. Ratnarajah, “Large-Scale MIMO Transmitters in Fixed Physical Spaces: The Effect of Transmit Correlation and Mutual Coupling”, IEEE Trans. Comms., vol. 61, no. 7, pp. 2794-2804, July 2013