A direction of arrival estimation method based on amplifier-integrated active metasurface is proposed to find multisource directions by a single-channel system. Nonuniformly periodic time modulation on the metasurface reduces the hardware complexity by taking advantage of the spectral resources. The amplifiers in the metasurface can function as modulation units to generate the required harmonics and enhance signal quality. An active 5x5-element metasurface prototype is fabricated and measured for multisource direction finding.

In this paper, Terahertz spectroscopy was combined with sparse deconvolution to determine the skin water content in vivo of skin directly underneath transdermal drug delivery patches. It was found that patches with a nonpermeable film backing hydrated the skin to a greater extent than permeable woven polyester fiber backed patches and that this hydration effect primarily occurs within the first 30 minutes of patch application and lasts for at least 24 hours.

A 240-GHz 4-transmitter 4-receiver 2-D multiple-input–multiple-output (MIMO) frequency-modulated continuous-wave radar transceiver was designed in a 130-nm SiGe bipolar CMOS technology with fT/fmax of 250/370 GHz using patch antennas on a single chip. The differential RF inputs are dc-coupled and current-matched to the differential on-chip antenna. At 240 GHz, measurements reveal a conversion gain of 24.8 dB, a single-sideband noise figure of 14.9 dB, and an output power of −2 dBm.

In this paper, an all-solid-state terahertz full-duplex upstream and downstream communication system working in the 220 GHz band is proposed with a 630m communication distance. The system performance and debugging algorithm are experimentally verified. The field test shows a communication distance of 630m under the communication speed of 20.8 Gbit/s per channel, with a bit error rate is less than 10−10. The estimated maximum communication distance of the system can exceed 1 km.

A multitarget wireless power transfer (WPT) system based on metasurface-holography multifocal beams and the design methods is presented in this article. A new field calculation formula is derived based on the Friis formula between the metasurface unit and the field point, which breaks the limitation of paraxial approximation and makes metasurface holography applicable in a wide-angle, long-distance, and nonplanar space. A metasurface with holography multifocal beams is demonstrated in a planar multitarget WPT system.