Breakthroughs in Microwaves: Programmable Terahertz Chip-Scale Surfaces and Systems—An Interview With Dr. Kaushik Sengupta

This article is the next in the periodic Breakthroughs in Microwaves series. This series is intended to highlight recent accomplishments, especially to those new to the field, by researchers in microwave engineering that hold promise. Up until about 15 years ago, there was a distinct dearth of applications in the region between approximately 100 GHz and the infrared region except in radio astronomy. In the last 10 to 15 years, however, there has been significant research in this frequency range. Of particular interest are fully integrated solutions that utilize standard integrated circuit processes, made possible by the sub-millimeter wavelengths inherent to this frequency range. Increased parasitics and coupling make design using standard microwave techniques problematic when scaled to the THz range, but new thinking has emerged that looks at the full problem in an electromagnetic sense with full co-design of all elements needed. This article first provides the reader information on previous THz technology applications and then presents an overview of traditional antenna beamforming structures. This introduction is then followed by a discussion of new programmable chip-scale electromagnetic surfaces as one of the solutions for THz applications. This article ends with a lively discussion with one of the leaders in this technology, Dr. Kaushik Sengupta, who discusses further insight into this pioneering technique