Research Of0.14Thz Frequency Multiplier Technology

In recent years, the research of terahertz (THz) communication system is under the spotlight. Stable and reliable solid state frequency source is the key of implementing THz communication system and application, while frequency multiplier methord is the major way to gain high-quality millimeter wave solid state source.In this paper, firstly introduced the characteristics of terahertz-wave and the mechanism and developments of the frequency multiplier, then introduced a wideband, highly efficient0.14THz doubler used the Schottky Varactor. The doubler which is based on quartz microstrip circuit integrated in waveguide cavity, uses wire bonding to implement diode grounding and apply external DC bias. Wideband electromagnetic coupling structures are implicated in various sections of doubler, the key components adopt schottky varactor diodes constituting anti-parallel pairs. Secondly, the varactor model is established and simulated, and the frequency doubling properties and input, output impedance are analyzed using the harmonic balance method. In order to realize this doubler circuit more accurately and effectively, three-dimensional finite element and nonlinear harmonic balance co-simulation are adopted to accomplish the design and simulation of waveguide-microstrip transition, microstrip low-pass filter, the arrangement section of varactor, DC bias circuit segment structure and the overall circuit performance of the0.14THz doubler. Finally, a0.14THz doubler is fabricated and tested according to the optimal simulation result.The test results indicate that, under65-75GHz driving frequency and20dBm driving power, the doubler gained a more than2mW output power in the130-144GHz band while the maximum output power is6.6mW at133GHz with efficiency up to7.15%. At the central frequency of140GHz, the output power is2.04mW with efficiency2.1%.