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 In Ga As/In P double heterojunction bipolar transistor（DHBT）. An inverted microstrip line is implemented to avoid a parasitic mode between the ground plane and the In P 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.

Electromagnetic Modeling of a Planar Structure Integrating a Via-Hole Using the Method FWCIP

We present in this paper a new formulation of the iterative method FWCIP “Fast Wave Concept Iterative Process” based on the wave concept. It calculates the electromagnetic parameters of a planar structure including a via-hole. This is modelled by the electromagnetic field that it creates in the structure. The validation of results found by this new formulation is ensured by comparison with those obtained by HFSS “high frequency structural simulator” software from Ansoft. They show that they are in good agreement.

Attenuation characteristics of monolayer graphene by Pi-and T-networks modeling of multilayer microstrip line

The impedances of Pi- and T- networks are obtained from the measured S-parameters of the multilayer microstrip line by modeling as an attenuator. The changes in impedances have been analyzed for the properties of various superstrates at the microwave ranges. With graphene on glass and graphene on quartz loadings, the impedances have increased and shifted towards lower frequency more in Pi-network than T-network modeling. This shift has become more prominent at higher frequency for the graphene on glass than graphene on quartz. A little increase in attenuation is found for graphene on glass or quartz than bare glass and quartz. The present study can be extended to obtain attenuation characteristic of any thin film by simple experimental method in the microwave frequencies.

A Numerical Modeling of Microstrip Line and Optical Waveguide with a Unified Compact Two Dimensional Finite Difference Time Domain Method

Several different anisotropic waveguides are studied with a unified compact 2 D finite difference time domain( FDTD ) method, and the accuracy and efficiency are confirmed by comparing with other numerical techniques.

New compact UWB microstrip-fed printed planar antenna for wireless applications

A proposed circular patch antenna with notch-cut fed by a simple microstrip line is described in this paper. It is designed for ultra-wideband （UWB） wireless communications and applications over the band 3.1-10.6 GHz. This antenna consists of a circular patch with notch-cut fed by a microstrip line, one transition step, and a partial ground plane. The 2： l voltage standing wave ratio （VSWR） bandwidth （Sll 〈-10dB） of the proposed antenna covers the entire UWB application range specified by Federal Communications Commission （FCC） that is from 3.1 to 10.6GHz. The proposed antenna is able to achieve an impedance bandwidth about 8.6 GHz （2.4-11 GHz）. The return loss, VSWR, radiation pattern, radiation efficiency, gain, distribution of the proposed group delay, and current antenna are included in this paper. The simulation results and proposed antenna design details are presented by CST Microwave Studio.

Design and simulation of a compact ultra-wideband bandpass filter with a notched band using multiple-mode resonator technique

A novel, compact, and highly selective ultra-wideband （UWB） bandpass filter with a narrow notched band is presented. Apart from having a basic structure of a slotline multiple-mode resonator （MMR） and microstrip feed lines, this novel design introduces a cross-coupling between the input and output feed lines to enhance the filter selectivity. The design strictly follows the theory and verified by electromagnetic （EM） simulation and experiments. In addition, the narrow notched band is introduced by embedding a pair of split ring resonators （SRR） in order to reject any undesired existing radio signals that may interfere with the Federal Communications Commission （FCC）-defined UWB band. By changing the structural parameters of SRR, it can be easily tuned to any desired frequency. This filter can be integrated in UWB communication systems and efficiently improve the interference immunity from undesired signals such as wireless local area network （WLAN）.