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.
Özetçe-Algılama alt sınırı (Limit of Detection-LOD) değeri, mikrosensörün anlamlı olarak algılayabileceği minumum konsantrasyon değerini vermekte olup, beyin hastalıklarında kullanılan mikrosensörün LOD değerinin 1µM dan daha küçük olması istenmektedir. Bu değere yaklaşamayan mikrosensörler deneylerde kullanılamamaktadır. Bu çalışma ile üretim sonucunda elde edilen sensörlerin LOD değerleri azaltılarak, duyarlılığının artırılması hedeflenmiştir. LOD değeri sensörün arkaplan (baseline) gürültüsü ile doğru orantılı olarak artmaktadır. Literatürde yapılan çalışmalarda arka plan gürültüsü filtrelenmeden elde edilen sensör verileri kullanılmıştır. Bu çalışmada ise, ham veriler dalgacık filtreden geçirildikten sonra kalibrasyon yapılarak, LOD değeri 3 kat iyileştirilmiştir. Anahtar Kelimeler -beyin sensörü; mikroelektrot, kalibrasyon; LOD; dalgacık dönüşümü.Abstract-Limit of detection (LOD) gives the concentration amount that a microsensor can detect. It is desirable to have a LOD value of 1µM for microsensors used in brain diseases. The ones that cannot reach this sensitivity value are disposed and cannot be used in the experiments. The goal of this study is to increase the sensitivity of the produced microsensors by decreasing their LOD values. LOD increases linearly by baseline noise. The sensor data is used generally without any baseline filtering in the literature. In this study, LOD values are enhanced 3 times as much by using wavelet filtering, compared with the ones where no filtering is used.
In this article, a detailed performance analysis of a novel flexible monopole antenna with a %141.46 impedance bandwidth in the 2.4-14 GHz UWB range is present. The antenna is fabricated on a flexible Kapton substrate with compact geometry for different technology applications under different bending conditions. The airbrush printed technique was preferred due to its advantages such as easy production, conductivity control, and no loss of surface waves. The antenna has dimensions of 82x57x0.125 mm3 and is fed by a coplanar waveguide transmission line. All necessary antenna simulations are performed using CST. According to the positions of identical antennas face to face, face to side, side to side, time-domain analysis is performed for the impact response analysis. The transmission coefficient characteristics (S21) and the group delay are measured for various bending conditions. Time and frequency domain analyzes show that the proposed UWB antenna has the much-needed stable performance in UWB antenna. The proposed UWB antenna has good performance over the operating spectrum for a flat and bending configuration.
This study presents a novel UWB flexible antenna with dual band-notched design for wearable biomedical devices. The proposed antenna is designed on Kapton Polyimide-based flexible substrate. This includes a CPW fed circular and triangle structure. The dual notched bands are realized by using two triangular-shaped defected ground structures. The first notched band (2.4−3.7 GHz) is generated for rejecting WLAN and WiMAX, the second notch (5.15-5.725 GHz) is generated for rejecting HyperLAN /2. The designed UWB antenna has approximately a bandwith of 150% (2.05-14 GHz) in simulation. Thus, the designed UWB antenna meets FCC standards. The antenna has an omnidirectional radiation pattern with a maximum gain of 12.7 dB in 8.4 GHz.The proposed antenna is fabricated with the low-cost airbrush printed technique. In this technique, a higher gain value is obtained by controlling the thickness of the conductive layer .Effect of flexibility on the antenna performance is tested for different configurations in the simulation and anechoic chamber environments. According to the results obtained, the overall performance is not affected except for the shift in frequency. Since the antenna has a UWB structure, the frequency shift that occurs in bending is at a tolerable level. The proposed UWB antenna is suitable for wearable biomedical devices, with a high UWB performance.
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