Comprehensive design and propagation study of a compact dual band antenna for healthcare applications

In this paper, a dual band planar inverted F antenna (PIFA) has been investigated for cooperative on- and off-body communications. Free space and on-body performance parameters like return loss, bandwidth, radiation pattern and efficiency of this antenna are shown and investigated. The on- and off-body radio propagation channel performance at 2.45 GHz and 1.9 GHz have been investigated, respectively. Experimental investigations are performed both in the anechoic chamber and in an indoor environment. The path loss exponent has been extracted for both on- and off-body radio propagation scenarios. For on-body propagation, the path loss exponent is 2.48 and 2.22 in the anechoic chamber and indoor environment, respectively. The path loss exponent is 1.27 for off-body radio propagation situation. For on-body case, the path loss has been characterized for ten different locations on the body at 2.45 GHz, whereas for off-body case radio channel studies are performed for five different locations at 1.9 GHz. The proposed antenna shows a good on- and off-body radio channel performance

Improving Bandwidth Efficiency in E-band Communication Systems

The allocation of a large amount of bandwidth by regulating bodies in the 70/80 GHz band, i.e., the E-band, has opened up new potentials and challenges for providing affordable and reliable Gigabit per second wireless point-to-point links. This article first reviews the available bandwidth and licensing regulations in the E-band. Subsequently, different propagation models, e.g., the ITU-R and Cane models, are compared against measurement results and it is concluded that to meet specific availability requirements, E-band wireless systems may need to be designed with larger fade margins compared to microwave systems. A similar comparison is carried out between measurements and models for oscillator phase noise. It is confirmed that phase noise characteristics, that are neglected by the models used for narrowband systems, need to be taken into account for the wideband systems deployed in the E-band. Next, a new multi-input multi-output (MIMO) transceiver design, termed continuous aperture phased (CAP)-MIMO, is presented. Simulations show that CAP-MIMO enables E-band systems to achieve fiber-optic like throughputs. Finally, it is argued that full-duplex relaying can be used to greatly enhance the coverage of E-band systems without sacrificing throughput, thus, facilitating their application in establishing the backhaul of heterogeneous networks.Comment: 16 pages, 6 Figures, Journal paper. IEEE Communication Magazine 201

Estimation of dielectric constant for various standard materials using microstrip ring resonator

Microstrip ring resonator (MRR) is known for dielectric constant determination and many studies used Teflon as a standard sample. However, there are many other materials available which able to perform better or equivalence as the Teflon in calibrating certain dielectric constant measurement. This paper presents simulation of the MRR to investigate frequency shift of materials for dielectric constant estimation using the CST STUDIO SUITE 2016 software. The MRR was designed on RT/Duroid®5880 substrate (εr = 2.2, tanδ = 0.0004) with 50 Ω matching impedance where microstrip width, substrate thickness and ring mean radius were 4.893, 1.575 and 14 mm, respectively to resonate at 2.65340 GHz. Teflon, Polyimide, Isola FR408, Arlon AD250, Arlon AD270 and Gil GML1032 were alternately selected to be placed on top of the MRR as a standard sample to obtain the frequency shift. The frequency shifts for the above materials were 2.56932, 2.46149, 2.44680, 2.53748, 2.52007 and 2.48608 GHz, correspondingly. The differences in frequency shift were used in NetBeans IDE 8.1 algorithm of Java for dielectric constant calculation. The results indicated that Polyimide and Arlon AD250 had the lowest and highest mean percentage error of 0.83536 and 1.76505 %, respectively. Hence, Polyimide might as well be the most suitable candidate as a standard sample in MRR technique for dielectric constant measurement