Hamza Nawaz

A compact microstrip patch antenna with circular snipped slot for GSM, Wi-Fi and WiMAX applications

A rectangular microstrip patch antenna with probe feed is proposed in this paper. The patch of an antenna has a key circular slot which is auxiliary truncated in circular style resulting three narrow bands of the most worthy and in-use wireless technologies of the modern age, that are GSM, Wi-Fi and WiMAX. The resonating bandwidths of the presented antenna ranges from 1.79 to 1.83 GHz for GSM 1800, 2.40 to 2.48 GHz for Wi-Fi and from 3.32 to 3.42 GHz used for WiMAX. The design process has been carried out in HFSS (High Frequency Structure Simulator) and antenna is fabricated manually, to assess and evaluate the real characteristics.

Ground plane tunable printed monopole antenna for wireless communications

A compact printed monopole antenna with tunable ground for adjustment of bandwidth is proposed. The achieved bandwidth is regulated by the length of ground plane. Presented antenna has five slits in its rectangular patch controlling the bandwidth and the frequency shifts. The simulated results are obtained using HFSS (High Frequency Structure Simulator). FR4 substrate of 30×24×1.6 mm3 is used for the fabrication. The measured results of prototype are acquired by network analyzer and anechoic chamber. The offered antenna is applicable for GSM (1800, 1900), UWB, UMTS (1900, 2100), Wi-Fi, WiMAX, Zig-bee, and Satellite Communication applications.

On-body textile antenna design and development for body-centric wireless communication systems

In this paper an X-band textile antenna is proposed having bandwidth of 200 MHz; the anticipated antenna is probe-feed rectangular antenna, having slots to achieve desirable results. Antenna is simulated and optimized using software HFSS- High frequency structure simulator and then fabricated using jeans as substrate and copper tape for patch and ground having antenna size of 35x45x1 mm. Proposed antenna achieve suitable and fine characteristics required for on-body applications like stable behavior throughout band, durable and low-profile, high and stable gain, omni-directional radiation patters, consistent current behavior, miniature in size and steady impedance matching. Results show little shift in frequency band when antenna is taken close to body; so the proposed antenna operational band is considered as the frequency band thats operational in both cases that are with or without human body.

MIMO antenna array for wireless local area networks

A MIMO antenna array has been presented in this paper, which has four rectangular microstrip patches as an antenna element(s). An elliptical slot is etched on every radiating patch. The antenna array is simulated in HFSS yielding resonating frequencies of 2.42, 3.49 and 4.98 GHz at S11 <; -10 dB making it applicable for WLANs. RT Duroid 5880 has been used as substrate. The gain ranges from 7 to 11 dB at all resonant frequencies with narrow bandwidth, improving interference rejection characteristics of the proposed antenna. Complete design procedure, comprehensive analysis of mutual coupling among the patches and radiation patterns are also discussed.

Design and analysis of two-dimensional InAlAs/InGaAs Single Hetero-junction Bipolar Transistor

The paper presents an InAlAs/InGaAs Hetero-junction Bi-polar transistor structure. The structure formation and performance analysis has been carried out using SILVACO software. Parametric analysis is carried out and results are presented in correspondence with the theory. Doping profile of proposed HBT is optimized to achieve appropriate current gain and maintain possibly low resistance in the base region to avoid recombination. Emitter area of 5×5 μm2 is used to achieve low off set voltage and high gain of 62dB while low doping enabled the device to operate effectively at high frequencies that is up-till 80GHz. Energy band diagram and effects of different layers are discussed showing efficient workability of the proposed structure.