Y. Fan

An Improved 110–130-GHZ Fix-Tuned Subharmonic Mixer with Compact Microstrip Resonant Cell Structure

This paper presents the design and fabrication of an improved low-loss 110–130 GHz subharmonically pumped mixer with planar Schottky diodes fabricated by Virginia Diodes Inc. The antiparallel pair of planar GaAs Schottky diodes flip-chipped onto a suspended microstrip is fully integrated with a radio frequency (RF) and an intermediate frequency (IF) filter. A compact microstrip resonant cell (CMRC) filter is for the first time introduced in a submillimeter mixer to replace the traditional low-and-high-impedance microstrip RF filter. The shorter size and wider stop-band of the CMRC filter improved the performance of the subharmonic mixer. The best single-sideband (SSB) conversion loss of 7.7 dB was achieved with 3.5 mW of local oscillator (LO) power at a fixed 59 GHz of LO frequency. Over an RF band of 20 GHz, the SSB conversion loss is below 11 dB.

UWB BPF with triple notched bands using novel dual-mode SIR and asymmetrical coupling structure

A novel ultra-wideband (UWB) bandpass filter (BPF) with triple notched bands is presented in this paper. The basic UWB BPF is realized by a Y-shaped multi-mode resonator. In order to reject the interfered signals, a novel dual-mode stepped impedance resonator is embedded to introduce dual notched bands at 5.85/8.13 GHz. Due to the asymmetrical coupling structure, another notched band centered at 7.12 GHz is implemented as well. Analysis of the filter has been done with classical even- and odd-mode methods. For verification, two sample filters have been simulated, fabricated, and measured. Good agreement is found between the simulations and measurements. The implementation area of the proposed filter is 14.7 × 10.1 mm2.

Frequency-reconfigurable TM010-mode reentrant cylindrical cavity for microwave material processing

This paper proposes a frequency-reconfigurable microwave reactor based on the reentrant cylindrical resonant cavity. It works with the TM010-associated mode and is able to resonate at every frequency in the range of 500–950 MHz, i.e., 62% tunable relative bandwidth. Considering the practical requirements of microwave processing, especially for the single processing capacity and the wide frequency bandwidth, the theory and design formula for the existing reentrant cylindrical resonant cavity are no longer applicable. Consequently, a new method to control the resonant frequency is proposed. The corresponding approximate design formulas are derived to show the relationship between cavity’s dimension and its electric properties (resonant frequency and quality factor). Their correctness is validated by the full-wave simulation. Furthermore, an effective feed method is developed to achieve good matching over a wideband frequency band. Within a volume of 502 mm3, relatively homogeneous -field can be generated at every operation frequency with the strength more than 105 V/m, while the single processed capacity keeps unchanged. Most of the microwave energy is concentrated within the processed region to achieve a high efficiency. This microwave reactor presents an excellent candidate in the application of a frequency-reconfigurable microwave processing system to recognize the optimal absorbent frequency for a special microwave reaction.

Design of a 118-GHz sub-harmonic mixer using foundry diodes

The paper presents the design and fabrication of a low-loss fixed-tuned 118 GHz subharmonically pumped mixer, using commercially available GaAs Schottky barrier diodes flip-chipped onto a suspended microstrip circuit. The simulation performance of the mixer exhibits a double side band (DSB) conversion loss below 10 dB over the range of 113–123-GHz, with 6 mW of local oscillator (LO) power. At 118 GHz, a DSB conversion loss of 12.6 dB is measured with 8 mW of LO power.

Research on Modeling of W-band Wide-band Total Power Radiometer Channel

The modeling and analysis of a W-band wide-band radiometer channel is investigated in this paper. In particular, special attention is given to the modeling of wide-band detector. Furthermore, a correction formula of the effective bandwidth of radiometer system is proposed with the influence of the properties of wide-band detector on the radiometer system performances considered. A behavioral model of total power radiometer channel is built, and system analysis is implemented using harmonic balance (HB) method to research the influences of wide-band detector on the radiometer channel.

Design of a 114GHz-135GHz passive tripler

We report on the design, fabrication and testing of a 114GHz to 135GHz passive tripler. No mechanical tuners and the simple circuit topology make it easy and cheap to fabricate the tripler. The circuit design, simulation and optimization of the tripler are carried out by using HFSS and ADS. The tripler comprises waveguide housing, microstrip circuits and a pair of United Monolithic Semiconductors (UMS) DBES105a GaAs schottky barrier diodes. Test data for the tripler show 3.5mW maximum output power with 3.7% efficiency at 128.7GHz. The conversion efficiency is above 1% from 126GHz to 135GHz.

Design of improved CMRC structure used in terahertz subharmonic pumped mixer

This paper presents a new improved compact, low-insertion loss, sharp-rejection, and easy to manufacture compact microstrip resonant cell (CMRC) structure [1] as microstrip or suspended-substrate microstrip lowpass filter (LPF) used in terahertz (THz) Subharmonically pumped mixer (SHM). In comparison to traditional high/low step-impedance filter used in SHM, this improved CMRC structure could shorten the circuit size by 50% and have advantages of better frequency selectivity property, as well as sideband rejection. By using suspended-microstrip transmission line structure, this improved CMRC structure improved its operation frequency up to THz. In addition, this improved structure also easy to manufacture through conventional lithography corrosion microstrip line technology. This improved CMRC structures circuit topology structure, equivalent-circuit model and full wave electromagnetic field simulation results and the SHM circuit topology model using improved CMRC structure are given.

A Novel Narrow Passband Millimeter Filter Using Suspended Improved Compact Microstrip Resonant Cell

A novel millimeter wave narrowband bandpass filter using improved suspended compact microstrip resonant cell is proposed in this paper. Compared to the traditional high/low step-impedance filter, the improved CMRC structure possesses good lowpass filter characteristics. Besides, it can shorten the circuit size over 50%. And a suspended CMRC has better filter characteristics of low return loss and sharper stopband rejection than a traditional CMRC. Based on the improved suspended CMRC, a novel millimeter wave narrowband BPF operating at center frequency of 40 GHz is designed and tested. The investigation results show that the BPF has low insertion loss below 1 dB in the narrow passband with a bandwidth of 10% and sharp rejection in the stopband.

Ka Band Novel Concise Sine Substrate Integrated Waveguide Bandpass Filter

A novel concise sine substrate integrated waveguide (SSIW), with both sides metallized via holes periodic undulation, is firstly proposed for developing bandpass filter (BPF) at millimeter frequency range. It has advantages of remarkable simplicity, compact size and low insertion loss. Simultaneously, a broadband microstrip to SSIW transition is proposed. Transition experimental results show less than 2 dB insertion loss at nearly whole Ka passband. Then, several Ka band SSIW BPFs with different passband widths and center frequencies are designed and fabricated. The experimental results demonstrated that the SSIW BPF passband width and center frequency could be designed by using different undulate amplitudes and periods of the SSIW.

A Concise Periodic Undulate Sine Rectangular Waveguide Bandpass Filter for Millimeter Wave Region

A novel sine rectangular waveguide (SRW) structure with either broad or narrow side periodic undulation is firstly proposed for designing bandpass filter (BPF) at millimeter wave frequency range. The bandpass characteristics of the SRW and two BPFs with a concise transition operated at millimeter wave atmospheric window frequency are studied. The SRW has the advantages of remarkable simplicity and completely closed environment without energy leaking. Besides, energy transmission mode in SRW is a quasi TE10 mode which is similar to that in rectangular waveguide, which means that a SRW can easily get transition to a rectangular waveguide. So, compared to the traditional waveguide cavity BPF using metal diaphragm, printed circuit substrate or complex cross section, the SRW can be directly connected to a standard waveguide without additional metal diaphragm or substrate. To verify the bandpass characteristics of SRW, Ka band SRW BPF was designed and fabricated. Experimental results show low insertion loss (< 0.2 dB) in the whole Ka passband and sharp, wide rejection in the stopband (below-20 dB), with good agreement with simulated results. Therefore, the SRW will have wide potential applications in millimeter wave frequency range.