This study presents a modeling of a new reconfigurable patch antenna with equivalent lumped circuit. Instead of intuitive approaches, including structural changes used in the literature, the proposed reconfigurable antenna design is based on minimum tuning effort using only capacitance adjustments. The proposed design resolves impedance mismatch problem, which occurs due to the nature of using several frequencies by only capacitance adjustments rather than physical structure adjustments. Reconfigurable patch antenna for 2.45 GHz (Wi‐Fi), 3.6 GHz (Wi‐max and 5G), 5.4 GHz (WLAN and 5G) was considered for novel design strategy. A complete equivalent circuit model is configured and validated through AWR software. Full wave analysis of the proposed antenna is performed using CST software. A prototype of the proposed antenna is also fabricated on a FR4 substrate with the dimensions of 48.19 x 38.36 x 1.53 mm3 and measured to validate the full wave analysis and circuit theory solution results. It is shown that the equivalent circuit model, full wave analysis, and measurement results are in good agreement.
The goal of this study is to analyze the specific absorption rate (SAR) distribution of the projected 5G frequencies below 6 GHz and at Wi-Fi frequency (2.45 GHz) on a human head, for eyewear device applications. Two separate tri-band printed dipole antennas for this purpose are designed and fabricated at operating frequencies of 2.45/3.8/6 GHz for prototype-1 and at operating frequencies of 2.45/3.6/4.56 GHz for prototype-2. In order to obtain the desired frequencies: first, the prototypes of the proposed antennas are fine-tuned via Computer Simulation Technology Microwave Studio (CST) and then fabricated on the FR4 layer. The reflection coefficient (S11) is tested and the simulation results are confirmed. In order to analyze the effect of wearing a pair of glasses' frame including a tri-band 5G antenna, a frame is designed and produced via 3D printer with polylactic acid material which has high dielectric constant (ɛ
r
= 8.1). The SAR results of the proposed antennas have been examined for the cases where the antenna is embedded in the frame and is used alone. Both cases were analyzed by using the homogeneous specific anthropomorphic mannequin and the heterogeneous visible human head phantoms and the results have been evaluated in terms of SAR10 g values.
Cancer is one of the most feared health problems today. Studies on cancer diagnosis and treatment are carried out intensively. In this study, a graphene-based antenna is proposed for cancer diagnosis and treatment with THz radiation therapy, which is a relatively new radiation technique. A graphene-based two-layer monopole antenna is designed for 1.65THz operation frequency. To change the bandwidth and radiation pattern without changing the operating frequency, a graphene ring is placed on the SiO2 substrate (2nd layer).Antenna performance is analyzed for reflection coefficient, realized gain, E-Field. The proposed antenna is obtained approximately %4 bandwidth. A peak gain of 8.52 dB is achieved at 1.65THz within the bandwidth. Antenna design is done in Computer Simulation Technology Studio Suite. It is expected that the results of the THz antenna will make a significant contribution to healthcare applications. The cancer treatment with THz is cheap, easy, and can be used without causing discomfort in patients.
In this Letter, a new wideband differential phase shifter is proposed by using a multi-section coupled line structure. S-parameter circuit equations and design parameters are calculated using even/odd mode and transmission line analysis techniques for a set of phase shifters (from 0 to 90 with a step of 10°) of the proposed device. The proposed form is the first work that adds multi-section structures on the coupled line to provide any desired phase shift to the same reference line. In addition, for specific applications such as hyperthermia, the beamforming is ensured to be at small angle steps (10°) to focus the signal to the correct spot. The device is modelled with full-wave electromagnetic simulator Computer Simulation Technology (CST). Ten prototypes of differential phase shifters are designed, manufactured, and tested for the accuracy of simulation results. The simulated and measured results are in good agreement with the theory and show a bandwidth of 20.4%, <2.7 phase deviation, and >1 dB insertion loss across the 2.2-2.7 GHz frequency range.
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