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 0.7dB in U-band and a stopband inhibition at 31.7dB in 110GHz.

A broadband 360 similar to 440 GHz subharmonic mixer based on Schottky diode designed by UESTC and fabricated by CETC-13 is presented. Diode modeling is described to simulate the electromagnetic environment due to geometry-dependent parasitic effects in the extremely high frequency band. The whole subharmonic mixer is optimized by means of combination of field and circuit in HFSS and ADS. Measured results show that the sub-harmonic mixer yields minimum conversion loss of 9. 99 dB at 406 GHz, while the conversion loss was less than 15 dB over 380 GHz to 430 GHz and less than 19 dB over 360 GHz to 440 GHz when LO power was 6 dBm at 210 GHz.

The design of a 0.22 THz sub-harmonically pumped mixer circuit was demonstrated. The circuit was based on anti-parallel pair of planar Schottky diodes from the CETC 13 with the co-simulation of electromagnetic ( EM ) software and circuit software . The conversion loss was measured at the fixed intermediate frequency ( IF ) of 10 MHz . The double sideband ( DSB ) conversion loss is less than 15 dB in the range of 175 GHz to 235 GHz, the bandwidth is 60 GHz. The best DSB conversion loss is 8.5 dB at 196 GHz. The measured result was well with the simulated result. The DSB equivalent noise temperature of is 1200 K at 216 GHz with the local oscillator(LO) power of 5.7 mW.

This paper describes the planar schottky diode based subharmonic mixers currently being developed at the EHF Key Laboratory of Fundamental Science of Universtity of Electronic Science and Technology of China. Hybrid and integrated GaAs Schottky diode based 330GHz and 420GHz subharmonic mixers are designed, fabricated and measured. Test results show that the minimum conversion loss of 330GHz monolithic integrated sub-harmonic mixer is 10.4dB at 328GHz, SSB conversion loss is less than 14.7dB from 320GHz to 340GHz when the LO power is 5mW; the minimum conversion loss of the 420GHz hybrid sub-harmonic mixer is 9.99dB at 406GHz, the SSB conversion loss is less than 15dB from 380GHz to 430GHz when the local power is 6dBm; the minimum conversion loss of the 420GHz heterogeneous integrated sub-harmonic mixer is 10dB at 419GHz and 422GHz, SSB conversion loss is less than 14.7dB over 400GHz to 440GHz frequency range when the LO power is 5.2dBm at 210GHz.

This design for mousing is made up of power control module, infrared sensor module, signal processing module, distance information transportation based on GSM and device of power grid. The design consists of two sets of conductors, separately linked by fire wire and null line and distributing alternatively. The major innovation is infrared sensor module with Fresnel lens, and that the infrared detecting area should be spread in one direction at least. When the mouse get into the infrared detecting area, the sensor signal of infrared detecting device is sent to power control module through signal element and then starts the device of power grid to power up to make the mouse be shocked or die. GSM module is adopted to tell that the mouse is caught successfully. This design can be placed in any position that the mouse is always out and no need of baits.

An 0.2 THz brodband unbalanced doubler multiplier was designed and realized based on four anodes in anti-series GaAs planar Schottky diodes. The Schottky diode was flip-chiped on the 75μm thick quartz. The circuit output power and efficiency was measured under the condition of small and large input power. The measured efficiency was bigger than 3% over the band of 210 GHz to 224 GHz with the input power between 10 mW to 15 mW under the condition of forward bias voltage. The peak efficiency is 7.8% at the frequency of 212 GHz. The measured efficiency was bigger than 3.6% over the band of 210 GHz to 224 GHz with the input power between 48 mW to 88 mW under the condition of self-biased . The peak efficiency is 5 . 7% at the frequency of 214 GHz . The biggest output power is 5.7 mW and 7.5 mW at the fixed frequency of 212 GHz when the input power is 132 mW under the condition of self-biased and reverse bias voltage of -0.8 V separately.

This design,fabrication and test of a 0.1 THz fundamental finline single-balanced mixer circuit on a single quartz substrate was presented.The local oscillator (LO) input signal was feeded from WR10 waveguide to a suspended microstrip line,the radio frequency (RF) input signal was also feeded from WR10 waveguide to a finline,and the intermediate frequency(IF) signal was taken to the output port through a LO-IF duplexer.This novel mixer circuit can omit a complex W-band filter compared to traditional mode.The circuit features simple design and easy assemblage.A pair of flip-chipped diodes rested on the 75 μm thick quartz substrate,which could improve the size precision of circuit,constitute the basic balanced mixing circuit.After the mixer circuit is fabricated,it owns a 90-110 GHz operating frequency,and its single side band conversion loss is better than 9dB when the IF is fixed at 50MHz.

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.

Because of the high electron mobility and two-dimensional electron gas concentration, InP based pseudomorphic high electron mobility transistors (PHEMTs) become one of the most promising three-terminal devices which can operate in terahertz. The InAs composite channel was used to improve the operating frequency of the devices . The two-dimensional electron gas ( 2DEG ) showed a mobility of 13 000 cm2/(V?s) at room temperature. 70 nm gate-length InAs/In0.53Ga0.47As InP-based PHEMTs were successfully fabricated with two fingers 30μm total gate width and source-drain space of 2μm. The T-shaped gate with a stem height of 210 nm was fabricated to minimize parasitic capacitance. The fabricated devices exhibited a maximum drain current density of 1 440 mA/mm (VGS=0.4 V) and a maximum transconductance of 2 230 mS/mm. The current gain cutoff frequency fT and the maximum oscillation frequency fmax were 280 and 640 GHz, respectively. These performances make the device well-suited for millimeter wave or terahertz wave applications.

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, it's 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%.

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.

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 4.51GHz.

GaN planar Schottky barrier diode (SBD) with an n(-)/n(+) structure was grown and fabricated on sapphire substrate. An n(+) GaN epitaxial layer with doping concentration of 8 x 10(18) cm(-3) was employed to reduce the parasitic resistance. An air-bridge structure and 50 mu m substrate thinning-down technique were adopted in order to reduce the parasitic capacitance. A record cut-off frequency (f(c)) of 902 GHz was achieved for GaN planar SBD with 2 mu m anode diameter.

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.

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.

Based on the SPICE parameters model of ideal diode, a modified small-signal equivalent circuit model of terahertz planar Schottky diode was built according to the physical structure of the diode. On-wafer device-under-test (DUT) structure based on CPW de-embed method was designed according to the equivalent circuit model of the diode. The small-signal S parameters were measured in the frequency range of 0.1-50 GHz and 75-110 GHz. All the parameters of diode model such as capacitances, resistances and inductances were extracted via the test results. Comparison between DC I-V resistances, empirical formula capacitances and high frequency parameters was made. Both of the capacitances and resistances at high frequencies were different from low frequencies. The built small-signal equivalent circuit model of terahertz planar Schottky diode was validated by simulation and the results of model simulation agree well with the DUT S-parameters. Complete equivalent circuit model and the testing method can more accurately represent the working state of the device under high frequency compared with the ideal diode SPICE model and the parameters of the traditional extraction method. This robust method is suitable for Schottky diode model extraction, which is useful for further nonlinear circuit design and optimization in terahertz wave frequencies.

In this letter, we report GaN planar Schottky barrier diodes (SBDs) with the DC and RF performance. The air-bridge structure is adopted to reduce the parasitic parameters. The cut-off frequency (f c ) of the diode with an anode diameter of 5 μm is calculated to be 655 GHz at zero bias. By using four anodes series GaN SBDs chip, a frequency tripler with a peak output power of 2.1 mW at 103.5 GHz is demonstrated for the first time.

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.