Browsing by Subject "Antenna feeders"
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Item Open Access Analysis of radome covered circular reflectors by complex source-dual series approach(IEEE, 1994) Oğuzer, T.; Altıntaş, A.; Nosich, A. I.Radiation from a two dimensional reflector antenna covered by a cylindrical radome is analyzed by the complex dual series approach. It is only performed for the electrically polarized incident field. The approach is based on the analytical numerical type regularization technique and not on the moment method. This method gives the exact solution with any desired accuracy and the directivity of the feed antenna can be modelled by using this method. The results can be thought as a reliable data for the validity of approximate solutions. The lossy case and the multilayer radome problems can be solved by the same method.Item Open Access Hybrid model for probe-fed rectangular microstrip antennas with shorting pins(IEEE, 2000) Mutlu, Selma; Aksun, M. İrşadiFor a probe-fed microstrip antenna, it is quite common to employ the cavity model to find the field distribution under the patch and other electrical properties. Therefore, a multiport analysis technique based on the cavity model is usually employed to predict the input impedance of a probe-fed microstrip antenna with shorting pins. However, this approach does not provide any information about the field distribution under the patch with the shorting pins, which is usually used to calculate the radiation properties of the patch antenna. In this study, shorting pins are considered as current sources with unknown amplitudes, and the field distribution under the patch is obtained as a linear superposition of the contributions from each source via cavity model. Then, the unknown current densities over the shorting pins are determined by implementing the boundary condition of the tangential electric field on the pins. This is a hybrid approach because the field distribution is calculated from the cavity model, and the current densities over the shorting pins are obtained from the point matching of the resulting field distributions over the shorting conductors. The input impedance results found from this approach agree extremely well with those obtained from the multiport analysis, which shows that the proposed approach predicts both the input impedance and the field distribution under the patch. In addition, since the feeding probe is also made of PEC, the electric field under the patch should satisfy the boundary condition on this conductor as well. In the application of the cavity model, this is always ignored, with the assumption that the source probe is too thin to affect the field distribution under the patch significantly. In this study, the boundary condition of the electric field is implemented over the source, and its effect on the field distribution, in turn on the resonant frequency, is demonstrated.Item Open Access Radiation characteristics of a 2D parabolic reflector antenna excited by the H-polarized complex source(IEEE, 2002-09) Oğuzer, T.; Nosich, A. I.; Altıntaş, AyhanThe aim of this paper is to obtain accurate reference data for relatively large and realistic reflector antenna systems. We concentrate on a parabolic reflector antenna in the H-polarization case. The directive primary feed is modeled by the complex source point method and the relative accuracy of the results is verified. © 2002 IEEE.Item Open Access Three dimensional microfabricated broadband patch and multifunction reconfigurable antennae for 60 GHz applications(IEEE, 2015-04) Hünerli H. V.; Mopidevi, H.; Cağatay, E.; Imbert, M.; Romeu, J.; Jofre, L.; Çetiner, B. A.; Bıyıklı, NecmiIn this paper we present two antenna designs capable of covering the IEEE 802.11ad (WiGig) frequency band (57-66 GHz and 59-66 GHz respectively). The work below reports the design, microfabrication and characterization of a broadband patch antenna along with the design and microfabrication of multifunction reconfigurable antenna (MRA) in its static form excluding active switching. The first design is a patch antenna where the energy is coupled with a conductor-backed (CB) coplanar waveguide (CPW)-fed loop slot, resulting in a broad bandwidth. The feed circuitry along with the loop is formed on a quartz substrate (at 60 GHz), on top of which an SU-8-based three-dimensional (3D) structure with air cavities is microfabricated. The patch metallization is deposited on top of this structure. The second design is a CB CPW-fed loop slot coupled patch antenna with a parasitic layer on top. The feed circuitry along with the loop is formed on a quartz substrate. On top, the patch metallization is patterned on another quartz substrate. The parasitic pixels are deposited on top of these two quartz layers on top of an SU-8 based 3D structure with air cavities. © 2015 EurAAP.Item Open Access A triple-band antenna array for next-generation wireless and satellite-based applications(Cambridge University Press, 2016) Razzaqi, A. A.; Khawaja, B. A.; Ramzan M.; Zafar, M. J.; Nasir, S. A.; Mustaqim, M.; Tarar, M. A.; Tauqeer, T.In this paper, a triple-band 1 × 2 and 1 × 4 microstrip patch antenna array for next-generation wireless and satellite-based applications are presented. The targeted frequency bands are 3.6, 5.2 and 6.7 GHz, respectively. Simple design procedures and optimization techniques are discussed to achieve better antenna performance. The antenna is designed and simulated using Agilent ADS Momentum using FR4 substrate (r = 4.2 and h = 1.66 mm). The main patch of the antenna is designed for 3.6 GHz operation. A hybrid feed technique is used for antenna arrays with quarter-wave transformer-based network to match the impedance from the feed-point to the antenna to 50. The antenna is optimized to resonate at triple-bands by using two symmetrical slits. The single-element triple-band antenna is fabricated and characterized, and a comparison between the simulated and measured antenna is presented. The achieved simulated impedance bandwidths/gains for the 1 × 2 array are 1.67%/7.75, 1.06%/7.7, and 1.65%/9.4 dBi and for 1 × 4 array are 1.67%/10.2, 1.45%/8.2, and 1.05%/10 dBi for 3.6, 5.2, and 6.7 GHz bands, respectively, which are very practical. These antenna arrays can also be used for advanced antenna beam-steering systems. Copyright © Cambridge University Press and the European Microwave Association 2014.