No abstract

Summary In this paper, a physical‐based SDD (symbolically defined devices) model of SBD (Schottky barrier diode) is proposed, in which conventional C‐V characteristics of diode SPICE model are modified by terahertz C‐V characteristics obtained by physical‐based simulation. Detail modeling method and design process are introduced in detail. To verify the accuracy of the SDD model, a 140 GHz high efficiency doubler is designed, fabricated, and measured. The measured maximum efficiency is 34.3% under 90 mW input power, and the 3 dB bandwidth is about 7 GHz, which agrees well with the simulated results. The proposed physical‐based SDD model is demonstrated to be more accurate than traditional diode SPICE model.

Metamaterial absorbers are an emerging and rapidly growing technology with potential applications in optoelectronics, such as refractive index sensing and energy harvesting. Herein, a dual-band terahertz metamaterial absorber is investigated by exploiting a patch of circular loops and cross-shaped structures. The designed absorber composes of a periodic metallic metasurface and a continuous reflector layer, which are separated by a benzocyclobutene dielectric film. The perfect absorptivity properties of the absorber, revealed at frequencies of 0.6 and 1.2 THz, can be flexibly designed by manipulating the geometrical dimensions. A sample of the designed absorber prototype is manufactured under a microfabrication process and measured through a terahertz time-domain spectrometer in free space. In addition, the potential application of the proposed terahertz absorber in refractive index sensing is analyzed and experimentally verified, which has an excellent unit sensitivity of 0.13 THz/RIU at 0.6 THz and 0.27 THz/RIU at 1.2 THz, respectively. The practicability in sensing applications is verified by coating polyimide and poly(dimethylsiloxane) dielectric films on the surface of the absorber, and the absorption frequency shifts at 1.2 THz are practically coincident with the simulated ones. This proposed prototype is an effective manner for terahertz metamaterial absorbers with potential applications in the sensor field.

A high-performance terahertz Schottky Barrier Diode (SBD) with a film-supported single mesa structure featuring a low structural parasitic with extremely low dielectric loss is reported in this brief. The fabricated substrate-free SBD is supported with a 2-3 µm polymer film using a low parasitic coupling capacitor of about 0.12 fF. It significantly reduces the electromagnetic coupling effect between the anode and cathode pads by 90% compared with the conventional structure of the same size. To reduce the Schottky junction capacitance at the anode, a submicron T-junction process is used with a low junction capacitance of 0.15 fF. The cutoff frequency calculated by the total capacitance of the diode is up to 4THz. The film-supported substrate-free terahertz monolithic integration circuit based on this film supported by a single mesa SBD has better performance in reducing the circuit dielectric loss, exhibiting a remarkable potential for high-frequency applications.

No abstract