Dong Xing

Wide stopband millimeter/terahertz lowpass filter using improved split ring resonator

Abstract In this paper, an improved split-ring resonator (ISRR) cell is proposed to realize wide stopband and miniaturization. This cell comprises a transverse microstrip branch in middle and two gaps on both sides with tapped-line input and output. The transmission coefficient is derived for ISRR based on the distributed circuit theory and odd-even mode theory. Then the novel low-pass filter (LPF) is designed by cascading several ISRR cells in terahertz and millimeter. The ISRR LPF possesses great characteristics such as wide stopband, deep transmission zeros and small size. Finally, the proposed filter was processed and tested in millimeter. The measured results show that the proposed filter has low insertion loss from 0.5 to 0.7 dB in U-band and a stopband inhibition at 31.7 dB in 110 GHz.

420 GHz subharmonic mixer based on heterogeneous integrated Schottky diode

This paper describes 420GHz subharmonic mixer based on heterogeneous integrated schottky diode designed by University of Electronic Science and Technology of China (UESTC) and fabricated by China Electronics Technology Group Corporation-13 (CETC-13). The whole circuit including schottky diodes is integrated directly on the 50 μm quartz instead of the traditional 12 um GaAs substrate thus the circuit is much easier to manufacture and the cost is much cheaper. The 3D model of schottky diode is built up in the HFSS to extract the parasitic parameters introduced by the diode package when the operating frequency is extremely high. Source-pull and load-pull methods are used to get the optimum RF, LO and IF embedding impedance in the ADS. Measured results show that the minimum conversion loss is 10 dB at 419GHz and 422GHz, SSB conversion loss is less than 14.7 dB from 400GHz to 440GHz when the LO power is 5.2 dBm at 210GHz.

A 330–500GHz 4th-harmonic mixer using schottiky diode

The letter presents a fourth-harmonic mixer based on planar schottky diode working at 330-500GHz. The result of simulation predicts that conversion loses well below 14dB from 369GHz to 477GHz with 6 dBm of local oscillator power. Therefore, the good performance of mixers in wide bandwidth and low conversion loss provides designers with a better choice.

Design of a 420GHz Sub-Harmonic Mixer based on planar Schottky diode

In this paper, a 420GHz Sub-Harmonic Mixer based on planar schottky diode is presented. The mixer circuit was fabricated on the 50um thick quartz substrate with a pair of anti-parallel flip-chipped schottky diodes. The planar schottky diode is fabricated in China Electronics Technology Group Corporation-13(CETC-13). Simulated results for the 420 GHz mixer achieved DSB conversion loss of 6.2dB@404GHz. The LO pumped power was 6dBm at 210GHz. The conversion loss was less than 8dB from 390GHz to 450GHz.

The design of 110GHz frequency tripler using GaN-based planar Schottky diodes

This paper presents the design of a 110GHz frequency tripler realized by GaN-based planar Schottky diodes. The complete multiplying circuit and diodes is fabricated with a 127-um-thick Rogers/RT5880 substrate and is mounted in a split waveguide block. Simulation result shows that output power is achieved 100mW in 110GHz with a constantly 1.5W driven power.

The design of 850GHz subharmonic mixer based on Schottky diodes

This paper presents the design and simulation investigation of a 850GHz low-loss subharmonical mixer based on GaAs Schottky barrier diodes. Our group analyzed the topology of subharmonic mixer, device modeling of Schottky diodes, the 3D electromagnetic passive circuits and the mixer circuitry with optimum performance. The antiparallel diodes pair is fabricated from China Electronics Technology Group Coporation-13 Institute, flip-chip mounted on a 25um-thick gallium-arsenide substrate.

A wideband 8th-harmonic mixer using Schottky diode

This letter presents the design of a wide band 8th harmonic mixer, using an anti-parallel pair of planar Schottky GaAs flipp-chip diodes fabricated onto a suspended quartz-based microstrip circuit. Simulations predict conversion losses are well below 23dB from 330 to 500GHz. The design offers an solution to simplify the local oscillator signal generation and realize the goal of low frequency conversion losses in wide band.

The design of a 0.33 THz frequency tripler

In this paper, we use suspended microstrip to design a 0.33 THz fequency tripler, in which a pair of Schottky varactor chips parallel is adopted. Considering the present processing technology, its easy for the unbalanced structure to provide bias to the diodes without an on-chip capacitor, which is essential to the balanced tripler scheme. The tripler consists of a waveguide housing, a pair of quartz microstrip circuits, a Rogers RT/duroid 5880 (tm) DC bias filter and a GaAs Schottky varactor chip. And when the input power is 23 dBm, The whole circuits simulation results indicates that the output power with 12.96% efficiency at 330.9 GHz, The 3 dB bandwidth for the tripler is above 7%.

Design of a 420GHz GaAs monolithic integrated sub-harmonic mixer

In this paper, a 420GHz GaAs monolithic integrated sub-harmonic mixer based on planar Schottky diode is presented. We combine the diode 3D model, nonlinear model and passive circuit by field-circuit method, then optimize the circuit through harmonic balanced method, finally study the GaAs monolithic integrated 420GHz sub-harmonic mixer. Simulated results for the mixer achieved DSB conversion loss of 7.161dB at 420.4GHz when the LO pumped power was 6dBm at 210GHz. The conversion loss was less than 9dB from 384GHz to 451GHz.

Design of a 664GHz wideband sub-harmonic mixer based on MASTER technology

In this paper, a terahertz wideband sub-harmonic mixer based on the Schottky anti-parallel diodes pair and MASTER technology is presented. The mixer circuit is fabricated on a 0.05mm quartz substrate including Schottky anti-parallel diodes pair, RF/LO transition, IF matching networks and filtering circuits. The diode circuit is fabricated on a quartz substrate directly by MASTER technology. The research analyzed the topology of sub-harmonic mixer, device modeling of Schottky diodes, the 3D electromagnetic passive circuits and the mixer circuitry with optimum performance. Conversion loss of the mixer is less than 10dB range from 513GHz to 705GHz when the LO pumped power was 5dBm at 260GHz to 400GHz.