A novel single‐feed wide band planar single layer circularly polarised (CP) slot antenna is presented. This low cost slot antenna consists of an L‐shaped feeding stub with metamaterial inspired complementary split ring resonator (MICSRR) and a wide 45° rotated symmetric square aperture. Broadband impedance and CP radiation bandwidth (BW) is achieved by using a novel artificial exciting stub with defecting CSRRs on it. By controlling the excitation phase of L‐shaped stub, a desirable circular polarisation can be generated and both impedance and CP BWs are considerably increased by up to 89%. The operating frequency ranges in S/C band about 1.5 octaves from 2.4–6.22GHz that covers most of the commercial wireless communication systems, such as WLAN (IEEE 802.11 (2.4/3.6/4.9/5/5.9GHz)), LTE and WiMAX (2.5/3.5/5.8GHz). The measured BWs of 3‐dB axial ratio and voltage standing wave ratio < 2 are around 91% (2.4–6.4GHz) and 89% (2.4–6.22GHz), respectively. The measured boresight gain is less than 6 dBic over the CP BW.
Abstract-This paper presents a new approach for measuring dielectric properties of materials. The proposed approach is based on applying the synthetic time domain reflectometry to a dielectric filled waveguide. The compromising measurement results show that this algorithm can be successfully applied for measuring other parameters of the materials. Also, the approach has been successfully applied to detect the discontinuities of as a multi-section microstrip line. This approach is very useful in measuring the electromagnetic parameters of the different liquids, gels, and solid materials.
In this paper, we present a novel flexible moon-shaped slot implantable antenna for neural recording systems and head implants. It covers both medical Industrial, Scientific and Medical band (2.45 GHz) and impulse ratio ultra-wideband (IR-UWB) frequency range (3.1–10.6 GHz) for forward and backward telemetry applications. It has a simple and miniaturized structure in comparison with the antennas reported in the other researches. Furthermore, for adapting with natural curvature of human head, a flexible substrate is chosen with a good antenna performance under the bending. The proposed antenna is analyzed in a multi-layer box model of head tissues to speed up the antenna design procedures. On the basis of the simulation results, we achieved the good impedance matching over the desired frequency range (S11below −10 dB). Far-field characteristics are considered, as well. The directivity is in suitable range for UWB short-range communications and its mean value is 3.84 dBi. Finally, to take into account patents’ safety regulations and the effective isotropic radiated power restriction in the desired frequency range, the maximum power of transmitter has been calculated. A phantom containing a mixture of sugar and water is used to test the fabricated antenna. The measured parameters are well matched to the full-wave simulation results.
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