Isenlik, T. | Yegin, K.
Article | 2013 | IEEE Transactions on Plasma Science41 ( 2 ) , pp.296 - 304
We present a simple design method for the hole-slot-type cavity magnetron. Our design model includes all principal parts of magnetron, namely, the cathode, the resonant system, the interaction space, and the magnetic circuit. We first find structural, electrical, and magnetic parameters using empirical formulas. Then, using empirical values as initial guesses, we build and simulate the 3-D model of magnetron in CST Particle Studio. In CST, we show that the eigenmode solver is essential for proper mode excitation; then, we use particle tracking and particle-in-cell simulations for the desired magnetron operation. For a fast convergen . . .t result, we study the impact of design parameters on the magnetron performance. We apply this design procedure to an X-band hole-slot-type magnetron with eight resonators. We believe that our method provides designers a simple, fast, and reliable tool for hole-slot-type magnetron design. © 2012 IEEE
Article | 2010 | Electromagnetics30 ( 7 ) , pp.589 - 608
A three-dimensional dyadic Green's function is derived for electromagnetic scattering due to a point electric current source radiating in the vicinity of a wedge with anisotropic impedance and perfect electric conductor faces. The anisotropic impedance face is characterized by surface impedances along directions parallel and orthogonal to the edge axis (principal anisotropy axis). Arbitrary surface impedance is assumed in one direction only (either parallel or orthogonal to principal anisotropy axis), and vanishing impedance is assumed on the other. Assuming reactive surface impedance, the derived forms involve a summation over an a . . .ngular wavenumber and a longitudinal spectral integral, which may be evaluated asymptotically to describe the fields in paraxial region, where the source and observation points are in close proximity to the apex but widely separated. The final asymptotic result reveals three different scattering mechanisms: edge-guided waves, surface waves, and guided waves in the classical sense. Numerical simulations are performed for capacitive and inductive surfaces using the asymptotic results. Simulation results are also compared to those of a commercially available electromagnetic field solver, which assumes uniform surface impedance. Copyright © Taylor & Francis Group, LLC
Article | 2013 | Electromagnetics33 ( 5 ) , pp.392 - 412
Isenlik, T. | Bilgiç, M.M. | Yegin, K. | Çiydem, M.
Conference Object | 2011 | 2011 30th URSI General Assembly and Scientific Symposium, URSIGASS 2011 , pp.392 - 412
Base station antenna array is designed to cover frequency range from 1710 MHz to 2170 MHz. An entirely different antenna feed structure which consists of an L-plate capacitive feed, is developed and a parasitic patch is optimized to meet target design specifications. The antenna is +/-45° dual polarization with dedicated channels for each polarization. A prototype of the antenna element is built and measured to corroborate simulation results. The antenna array for BSA is designed to have an 18 dBi system gain with a VSWR less than 1.5 over the entire frequency band. © 2011 IEEE.
Isenlik, T. | Yegin, K. | Barkana, D.E.
Article | 2019 | IET Microwaves, Antennas and Propagation13 ( 12 ) , pp.2102 - 2109
It is well known that the beamwidths of horn antennas are inversely proportional to frequency. Previous studies point to minimum ±12% beamwidth stability within a maximum of 2.5:1 bandwidth (BW) ratio. To extend this BW, a design methodology for broadband double-ridged horn antenna (DRHA) is proposed and applied to 4.5–18 GHz frequency band. Firstly, a conventional DRHA is designed and studied to compare the beamwidth variation of wideband horn antennas. By explicitly addressing the shortcomings of conventional DRHA, DRHA is redesigned and near-constant beamwidth DRHA is proposed using the modifications implemented on the sidewalls. . . . The antenna utilises ridges to extend the frequency band, unlike other wideband constant beamwidth horns. The authors show that ridged horns, whose dimensions are appropriately designed and modified, can have stable beamwidths. Then, properly positioned curved pinwalls are designed to provide considerable improvement in H-plane beamwidth constancy. Broadband double-ridged waveguide-to-coaxial adapter is also designed for 50 ? reference. The prototype is manufactured, and the measured antenna exhibits wideband characteristics with 30.9° ± 2.7° half power beamwidth in H-plane over 4:1 BW ratio. This variation corresponds to ±8.7% beamwidth stability along with the target frequency band. © The Institution of Engineering and Technology 2019