Terahertz frequency band (0.1 ~ 10 THz) can provide ultra-high transmitting rates for massive emerging applications. However, due to the radio frequency impairments and limited signal processing property of baseband devices, it is difficult for the current terahertz communication systems to be used in real applications. In this work, we report a 0.22 THz communication system, which can provide 84 Gbps air interface rate over 1.26 kilometers distance. Such a system is underpinned by three breakthroughs, namely, integrating the reported terahertz wireless communication system, redesigning the signal processing in baseband devices, and increasing the cut-off frequency and transmitting power of radio frequency component by parameter optimizing. Being applied to realize the real-time transmission of the uncompressed 8K ultra high-definition video in the 31st International University Sports Federation in Chengdu, China, this work is a leaping advancement to enable terahertz systems from experiment to promising applications.

Terahertz (THz) science and technology promise unique applications in high‐speed communications, high‐accuracy imaging, and so on. To keep up with the demand for THz systems, THz dynamic devices should feature large phase shift modulation and high speed. To date, however, only a few devices can efficiently manipulate the phase of THz waves. In this paper, we demonstrate that efficient phase modulation of THz waves can be addressed by an active and enhanced resonant metamaterial embedded with a nanostructured 2D electron gas (2DEG) layer of a GaN high electron mobility transistor (HEMT). The enhanced resonant metaunit couples the traditional dipolar and inductance‐capacitance resonances together to realize a coupling mode with enhanced resonance. Embedded with the nanostructured 2DEG layer of GaN HEMT, the resonance intensity and surface current circuit of the enhanced resonant mode in the metamaterial unit can be dynamically manipulated by the electrical control of the carrier distribution and depletion of the 3 nm 2DEG, leading to a phase shift greater than 150° in simulation. In the dynamic experiments, a 137° phase shift was achieved with an external controlling voltage of only several volts in the THz transmission mode. This work represents the first realization of a phase shift greater than 100° in a dynamic experiment in transmission mode using an active metamaterial structure with only a single layer. In addition, given the high‐speed modulation ability of the HEMT, this concept provides a promising approach for the development of a fast and effective phase modulator in THz application systems.

This paper presents our study on a high power 220GHz frequency tripler based on a pair of GaN planar Schottky barrier diode chain chips. In the proposed frequency tripler, the pair of diode chips was directly mounted across the metal diaphragm in parallel with the opposite polarisation inside the rectangular waveguide. The RF field is tuned to its hot-spot, coupling directly onto the diode chains, turning on a diode chain at a time in an alternative manner. Unlike the traditional ones, in order to achieve a better heat dissipation, the diodes are directly connected with the metal block. Benefitting from a better heat dissipation and the power endure capacity of GaN material, the proposed tripler can work well under a watt level input power. The simulated tripler frequency conversion performance agrees with the measurement results very well. In addition, the experiments show that the frequency tripler can endure a maximum input power of 1.1W. And the output power of this frequency tripler is 17.5mW at 219.5GHz driven by 900mW input power with the best efficiency of 1.93%.

A novel silicon-on-insulator (SOI) high-voltage device structure with double-sided trenches on the buried oxide layer (DT SOI) is proposed and its breakdown characteristics are investigated theoretically and experimentally in this letter. Theoretically, the charges implemented in the DTs, whose density changes with the drain voltage, increase the electric field in the buried layer and modulate the electric field in the drift region, which results in the enhancement of the breakdown voltage (BV). Experimentally, the BV of 730 V is obtained for the first time in SOI LDMOS with DT on 20-mum SOI layer and 1- mum buried oxide layer

A high precision high-order curvature-compensated bandgap reference (BGR) compatible with standard BiCMOS process is presented in this paper that is capable of working down to input voltages of 1.6 V with 1.285 V output voltage. High-order curvature correction for this reference is accomplished by a novel piecewise technique, which realizes exponential curvature compensation in temperature range, and a logarithmic compensation term proportional to V_T In T in higher temperature range through simple structures. Experimental results of the proposed BGR implemented in 0.5-μm BiCMOS process demonstrate that a temperature coefficient (TC) of 5 ppm/°C is realized at 3.6 V power supply, a power-supply noise attenuation (PSNA) of 70 dB is achieved without filtering capacitors, and the line regulation is better than 0.47 mV/V from 1.6 V to 5 V supply voltage while dissipating a maximum supply current of 25 μA. The active area of the presented BGR is 180 μm × 220 μm.

A new silicon-on-insulator (SOI) power MOSFET structure is proposed, in which buried oxide step structure (BOSS) is replaced by a buried oxide double step (BODS). Numerical simulations are performed to demonstrate that higher breakdown voltages are obtained resulting from a higher electric-field peak introduced near the BODS, and higher impurity concentration is depleted due to thin-film SOI than that in the conventional SOI and BOSS structure.