Oupeng Li

Graphene resonant channel transistor

Two kinds of doubly clamped beam graphene resonant channel transistors (RCTs) with local gate configurations, fabricated by direct exfoliation and transfer are presented in this paper. The RCTs are actuated and detected directly by using a vector network analyzer. And the measurement results show that the exfoliation RCT and transfer RCT have resonant frequencies of ~34MHz at 77K and ~88MHz at 300K, respectively. The operation principle of radio frequency (RF) RCT is detailed in this paper. And a compact electrical equivalent circuit model has been given out based on the analysis of electromechanical model of doubly clamped beam and field effect transistor theory. The results show that excellent agreements have been achieved between the experimental results and the simulation results. With the proposed compact model, the RCTs can be useful for developing high sensitivity sensor, or in the perspective of high quality RF filters by using graphene nano-electromechanical systems(NEMS).

140 GHz power amplifier based on 0.5 µm composite collector InP DHBT

This paper presents a high gain, medium power amplifier for D band application based on 0.5 μm composite collector InP double heterojunction bipolar transistor (DHBT) process. The power amplifier has four ways that combined with a T-junction power combiner. And each way has four stages HBT to provide a high gain performance. The measurement results demonstrate a peak gain of 23.6 dB at 75GHz and at 140GHz the gain is 21.89 dB. The saturation output power is 13.7 dBm at 140GHz with DC power consumption 250mW.

A High-Frequency Compact Model for Graphene Resonant Channel Transistors Including Mechanical Nonlinear Effects

This paper presents a physical-based high-frequency nonlinear model of graphene resonant channel transistors (G-RCTs), including a nonlinear electromechanical model of doubled clamped graphene mechanical resonators. To accurately describe the temperature-dependent modal dispersion, both bias- and temperature-dependent effects are considered. The temperature-dependent built-in strain, the bias-based electrostatic force, and the spring restoring force, including the nonlinear term upon deformation, are used to describe the mechanical motion of the suspended beam. The nonlinear model is validated by the measured results of G-RCTs, which indicate that our model can predict the experimental results well. Moreover, the nonlinear effects, including harmonic distortion, third-order intermodulation distortion, and the hysteresis and nonlinear behavior of G-RCTs, are also studied. The results show that the nonlinear physical model can predict the response of G-RCTs very well. These results also show that the mechanical nonlinearity has strong effects on nonlinear distortion for G-RCTs. The nonlinear equivalent circuit model could be useful for nanoelectromechanical system in the applications of high-frequency integrated circuits.

Accurate multi-bias equivalent circuit model for graphene resonant channel transistors

This paper presents a compact small signal equivalent circuit model of graphene resonant channel transistors (G-RCTs) suitable for different bias conditions. The model combines a bias dependent model for a GFET with a continuum mechanics model for 2-D graphene membrane. The model has been validated by graphene resonators fabricated by mechanical exfoliation techniques and transfer techniques. The characterization of G-RCT at very wide gate bias range with Vgs from -20 to 20V is predicted for the first time by using equivalent circuit model, which proves the validation of the proposed model. With the proposed compact model, the RCTs can be useful for developing high sensitivity sensor, or in the perspective of high quality RF filters by using graphene nano-electromechanical systems (NEMS).

A G-band terahertz monolithic integrated amplifier in 0.5-μm InP double heterojunction bipolar transistor technology*

Design and characterization of a G-band (140–220 GHz) terahertz monolithic integrated circuit (TMIC) amplifier in eight-stage common-emitter topology are performed based on the 0.5-μm InGaAs/InP double heterojunction bipolar transistor (DHBT). An inverted microstrip line is implemented to avoid a parasitic mode between the ground plane and the InP substrate. The on-wafer measurement results show that peak gains are 20 dB at 140 GHz and more than 15-dB gain at 140–190 GHz respectively. The saturation output powers are −2.688 dBm at 210 GHz and −2.88 dBm at 220 GHz, respectively. It is the first report on an amplifier operating at the G-band based on 0.5-μm InP DHBT technology. Compared with the hybrid integrated circuit of vacuum electronic devices, the monolithic integrated circuit has the advantage of reliability and consistency. This TMIC demonstrates the feasibility of the 0.5-μm InGaAs/InP DHBT amplifier in G-band frequencies applications.

An improved through line de-embedding method with even-odd mode measurement

This paper presents a new S-parameter matrix calculation based de-embedding methodology. In this method, a noval even-odd mode measurement is proposed to correct the error in traditional through line de-embedding methodology. The influence of the asymmetric input and output stub is canceled. A comparison of the different de-embedding methods for active device (0.7 μm InP DHBT) are performed up to 66 GHz, the results showed that the proposed method has good accuracy and suitable for millimeter-wave (mmWave).

W-band InP DHBT MMIC Power Amplifier

In this paper, a monolithic W-band Power amplifier (PA) is presented by using 1μm InP/InGaAs/InP double heterojunction bipolar transistor (DHBT) technology. The PA is consisted by 2 stages 2×1μm and 3 stages 4×1μm emitter width transistors. The total circuit shows small signal gain is above 15dB from 90GHz to 96GHz, and the simulated saturation output power reaches 18.5dBm@94GHz. The chip area is only 1.61mm×1.03mm. This W-band power amplifier MMIC is now being fabricated in progress on the NEDI compound semiconductor process line.

W band power amplifier based on 1 µm InP DHBT

In this paper, a W-band power amplifier (PA) is presented by using 1 μm emitter length InP/InGaAs DHBT technology. The PA is consisted by 2 stages cascode cells and a common-emitter cell. The total circuit achieves more than 14 dB associate gain from 90 GHz to 98 GHz with input return loss greater than 30 dB and output return loss greater than 7 dB. The saturation output power reaches 18.5 dBm at 94 GHz. The chip area is 1.5 mm×1.1 mm.

60GHz GaAs MMIC low noise amplifier

In this paper, a monolithic V-band low noise amplifier (LNA) is presented by using 0.15μm gate length GaAs/InGaAs/AlGaAs pseudomorphic HEMT technology. The LNA is consisted by 4 stages 4×30μm gate width transistors. The total circuit achieves 2.2-2.7 dB noise figure with more than 16dB associate gain from 57GHz to 66GHz, and the saturation output power reaches 15dBm. The chip area is 2.1mm×1.5mm.

A D-band divide-by-6 injection-locked frequency divider with Lange-coupler feedback architecture in 0.13 µm SiGe HBT

A D-band divide-by-6 injection-locked frequency divider (ILFD) is presented. The basic mechanism of high division ratios frequency divider is investigated. The circuit employs a wideband microstrip Lange coupler, a microstrip delay line and a pair of Cascode transistors to form a feedback loop for enhanced divide-by-6 operation. The proposed ILFD is fabricated with chip size of 0.7 × 0.9mm2 in a 0.13 μm SiGe HBT technology. The losses of WR-6 waveguide and 170-GHz probe in measurement setup are calibrated accurately by employing the open-short-load approach in a terminated two-port network. Through varying the operating voltage, the free-running oscillation frequency of the circuit can be changed, which results in an effective frequency-division locking range of 135 to 150.2 GHz while consuming 5.25 to 14.4mW including the output buffer amplifier. A phase noise of −121.58 dBc/Hz at 1MHz offset is achieved at 150.2GHz.