BiCMOS chip delivers 370 GHz beam steering for next gen communications

August 30, 2017 //By Julien Happich
Researchers from the University of California, Davis have designed a novel SiGe chip operating at tunable frequencies from 318 GHz up to 370 GHz, with a bandwith of 52 GHz. What's more, the chip's radio beam can be steered to precise locations, which could make it useful to transmit data at Gbit/s rates.

 


Graduate student Hossein Jalili displays the
millimeter-wave/terahertz phased array chip that
he and Assistant Professor Omeed Momeni prototyped
in the UC Davis Millimeter-Wave Research Center in
the College of Engineering.
Maria Ines Perez-Vargas/UC Davis.

Presenting their results at the 2017 IEEE International Solid-State Circuits Conference in a paper titled "A 318-to-370 GHz Standing-Wave 2D Phased Array in 0.13μm BiCMOS", the researchers disclosed the symmetrical architecture of a millimetre-sized chip able to operate broadband frequency tuning (52 GHz) independently of beam steering over an angle of 128° in the E plane and a maximum beam steering angle of 53° in the H plane.

Built using a 0.13μm SiGe BiCMOS process, the 2x2 array structure consists of four λ-size standing-wave (SW) oscillator unit cells, each made of two half-cell SW oscillators facing each other and coupled together through transmission lines in the collectors and λ/4 lines at the emitters of transistors (see figure 1).

The two half-cells operate out of phase resulting in a virtual ground along the line of symmetry and cancelation of fundamental frequency and other odd harmonics while combing the desired 4th harmonic, the paper reports.