Numerical Analysis and Measurement of Electric field Strength inside GTEM Cell at GSM Frequencies

A miniaturised gigahertz transverse electromagnetic (GTEM) cell is designed and fabricated to generate uniform electric (E-) field, essential for studying the radio frequency exposure effect on tissue equivalent liquids at global system for mobile (GSM) communication frequencies (914 MHz and 2.10 GHz). The simulation procedure is discussed and its results are compared with measurement data. The E-field strength inside the GTEM cell is scanned using a microstrip based E-field probe and complete uncertainty evaluation procedure is discussed. Theoretically, simulated and measured E-field strength is reported with expanded uncertainty

Compact Wideband Microstrip Patch Antenna Design for Breast Cancer Detection

The current breast cancer detection techniques are mostly invasive and suffer from high cost, high false rate and inefficacy in early detection. These limitations can be subdued by development of non-invasive microwave detection system whose performance is predominantly dependent on the antenna used in the system. The designing of a compact wideband antenna and matching its impedance with breast phantom is a challenging task. In this paper, we have designed a compact antenna matched with the breast phantom operating in wideband frequency from 1 to 6 GHz capable to detect the dielectric (or impedance) contrast of the benign and malignant tissue. The impedance of the antenna is matched to a cubically shaped breast phantom and a very small tumor (volume=1 cm3). The antenna is tuned to the possible range of electrical properties of breast phantom and tumour (permittivity ranging from 10 to 20 and conductivity from 1.5 to 2.5 S/m). The return loss (S11), E-field distribution and specific absorption rate (SAR) are simulated. The operating band of antenna placed near the phantom without tumor was found to be (1.11-5.47)GHz and with tumor inside phantom is (1.29-5.50)GHz. Results also show that the SAR of the antenna is within the safety limit

Development of E Waste based Composite Microwave Absorbing Material

Microwave absorbing materials (MAMs) are widely researched due to their use in many practical applications including both civil and defense sectors. Irrespective of the humongous efforts of various researchers, the development of a wide bandwidth, thin coating thickness, and low-cost microwave absorber is still a challenging task. The existing materials have not been able to meet all the specifications together at once and require a trade-off in the performance parameters. In this paper, we have empirically corroborated a cost-effective technique using E-waste material for synthesising composite MAM. It is herein shown that the addition of different wt% of copper, graphite, and titanium dioxide in the E-waste successfully resulted in enhanced absorption due to altered electrical properties of the E-waste suitable for microwave absorption. The multilayering technique with the help of a genetic algorithm has also been used to broaden the bandwidth. As a result, a three-layer MAM with the total coating thickness of 3.2 mm has been synthesised showing the wideband absorption bandwidth of 8.47 GHz in the frequency range from 6.92 to 15.39 GHz. The results suggested that microwave absorption of E-waste can be drastically improved by appropriately tailoring electrical parameters such as permittivity and permeability

ACCURATE AND PRECISE E-FIELD MEASUREMENT FOR 2G AND 3G NETWORKS BASED ON IEEE STD. 1309-2013

This article elaborates the theoretical and measurement technique to evaluate precise and accurate electric (E)-field strength for frequency range 0.8-2.4 GHz (2G and 3G communication spectrum). The E-field using a probe is precisely measured inside an indigenously designed transverse electromagnetic (TEM) cell as per IEEE Std. 1309-2013. Key parameters for precise E- field measurement are explicated with their measurement results such as probe linearity, field distortion, and mismatch losses. E-field strength of probe has been reported 9.91 V/m with an expanded uncertainty (k approximate to 2) of +/- 0.58 V/m for +18 dBm fed power at 915 MHz frequency