A 300 GHz power‐combined frequency doubler based on E‐plane 90°‐hybrid and Y‐junction

Abstract

In this article, a 300 GHz power‐combined frequency doubler using two chips in a single waveguide block is developed to acheive high power handling capability. Each doubler chip integrated with six diodes on a 5‐μm‐thick GaAs membrane is manufactured by the LERMA‐C2N Schottky process. In the power combining architecture, the input wave is split into two paths with a 90° relative phase shift by using a 90° hybrid coupler, and the in‐phase E‐field power combining between the output ports is provided by an E‐plane Y‐junction. This doubler can enjoy comparable performance of bandwidth and efficiency as the single‐chip version except with the twice input power handling. Partial results including ~8 mW output power and ~15% efficiency have been delivered in the band of 260‐310 GHz when pumping with 20‐60 mW input power, which indicates that this dual‐chip doubler can work availably. Such E‐plane power‐combined doubler can be further served to drive high‐power terahertz multiplier chains, and also pump multipixel heterodyne detectors.

A Review of Terahertz Sources Based on Planar Schottky Diodes

“…Power synthesis technology based on monolithic integration. (a) Monolithic integration process for planar Schottky diodes and power synthesis technology, including circuit images (top) and experimental output power up to 1.3 mW (bottom) [116] ; (b) A chip based on a power synthesis of 160 GHz terahertz source (top) with a maximum output power of 70mW and a maximum efficiency of 30% (bottom left) and output power and isolation port power (normalized to available input power) of the quadrupler versus frequency (bottom right) [117] (right) [120] ; (b) A single waveguide block with dual chip of 300GHz power combined frequency doubler (left) and test results (right) [122] of W-band power amplifier based on GaN material has reached the watt level [127] . GaN is a kind of direct bandgap semiconductor, but its bandgap width is much larger than GaAs, which makes GaN-based diodes have higher intrinsic temperature and can be used in the manufacture of high-power devices [128] .…”

“…In 2018, Jeff Powell reported a monolithic integrated power synthesis frequency doubler [120] , as shown in Fig. 11(a).…”

“…11. (a) Structure of a monolithic 180GHz frequency doubler based on power synthesis (left) and experimental test results(right)[120] ; (b) A single waveguide block with dual chip of 300GHz power combined frequency doubler (left) and test results (right)[122]…”

H-Plane Waveguide In-Phase Power Divider/Combiner With High Isolation Over the WR-3 Band

“…The interest in modern terahertz instruments has enabled a great demand for abundant active devices and passive components, such as surface wave oscillators [3][4], backward wave oscillators (BWOs) [5], klystrons [6], multipliers [7], mixers [8], on-chip amplifiers [9], orthomode transducers, antenna arrays, filters and power dividers (also named as power combiners) [10]. The further improving of output power from an individual solid-state device is difficult due to the inherent saturated nonlinearity at terahertz frequencies, thus the need for power combining method becomes evident [11][12]. In addition, the 3-dB power divider/combiner/coupler has also become one of basic circuits for terahertz sideband separating mixers [13] and multi-pixel receivers [14].…”

“…At sufficiently high frequencies, namely, from the submillimeter wave band to the terahertz band, the loss of substrate-based planar transmission lines is significantly larger than that of the metal sealed waveguides [15]. Due to their advantages, such as the ease of fabrication and interconnection, rectangular waveguides are preferred for the realization of the key components in terahertz systems [9][10][11][12][13][14]. Several classical waveguide power couplers based on the T-/Y-junction operating in the terahertz band have been produced by the silicon micromachining [16][17][18][19] or the 3D printing technologies [10].…”