Transmitarrays for 5G and Beyond

Project: Research

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Multi-Gigabit-per-second (Gbps) wireless communication has been successfully demonstrated inrecent years. In 2013, German scientists established a 20 m wireless communications link of 100Gbps operating at 237.5 GHz. In 2015, French researchers in collaboration with Tektronixpushed the frequency up to 0.4 THz and achieved 32 Gbps wireless transmission for a distanceof 25 m. On the other hand, multiplexing 8 orbital-angular-momentum (OAM) modes, 32 Gbpsdata stream was transmitted for a short range of 2.5 m at 28 GHz by a team from the Universityof Southern California, University of Glasgow and Tel Aviv University in 2014. With thesedevelopments, Terabit-per-second (Tbps) wireless communication will no longer be a dream butreality within the next decade. Innovations on antenna design are required to meet newchallenges in meeting the link budget as well as different multiplexing schemes.In this project, we embark on designing high gain THz transmitarray antennas with multilayeredmetasurface technology. With proper balance between transmission phase and magnitude, ourpreliminary simulation results reveal a 20% bandwidth for 1-dB gain drop, peak gain of 27.2 dBiat 240 GHz and peak aperture efficiency of 44.5% for a 2-layered metasurface with an F/D of0.88 fed by a horn antenna. These numbers increase to 23%, 28.9 dBi and 68.7%, respectively,for the 3-layered structure. We also propose to study different pixel geometries and grid patternsto improve the antenna performance. By properly designing the transmission phase, we cancontrol the wavefronts and polarizations of the antenna radiations. We propose to designtransmitarrays with capacity of linear-to-circular-polarization, co-to-cross-polarization, and dual-polarizationradiations. Similarly, we can also design transmitarray antennas with spiral phasefronts of different orders and higher orders can be achieved by stacking metasurfaces of lowerorders, which have been confirmed by our preliminary THz simulation studies. Lastly, wepropose to investigate OAM transmitarrays at THz frequency. In addition to our existingcontinuous wave (up to 1.1 THz) and time-domain (up to 3.5 THz) measurement facilities, weare currently building a THz near-field scanner (up to 1.1 THz) with 5 m resolution in eachdimension. Validation of the phase fronts and far-field radiation patterns of the designedtransmitarrays will be conducted.Through this project, we aim at contributing to bridging the THz gap and providing enablingtechnologies for the Hong Kong electronic industry to develop critical components for ultra-highspeed wireless communication.


Project number9042339
Grant typeGRF
Effective start/end date1/09/168/10/20

    Research areas

  • transmitarrays , Terahertz , metasurfaces , circular polarization , dual polarization