Showing 6 results for Khalaj-Amirhosseini
M. Khalaj-Amirhosseini, M. Moghavvemi, A. Attaran,
Volume 7, Issue 4 (December 2011)
Abstract
This paper proposes an idea to modify the conventional Wilkinson power dividers to have physically spaced output ports. The well-known internal resistor of Wilkinson power divider is now connected to output ports by two additional transmission lines to create a triangular shape power divider. Several modified power dividers are designed at frequency of 1.0 GHz and one of them is fabricated and measured. The measured results of the fabricated diplexer have very good agreement with the theoretical results.
Prof. M Khalaj-Amirhosseini,
Volume 11, Issue 4 (December 2015)
Abstract
The ideal analysis of planar diodes in Temperature Limited Region is presented. Two types of relations are obtained for electric potential and electric field distributions one accurate but implicit and the other almost accurate but explicit.
M. Khalaj-Amirhosseini, M. Nadi-Abiz,
Volume 16, Issue 2 (June 2020)
Abstract
Phase Perturbation Method (PPM) is introduced as a new phase-only synthesis method to design reflectarray antennas so as their sidelobe level is reduced. In this method, only the reflected phase of conventional unit cells are perturbed from their required values. To this end, two approaches namely the conventional Optimization method and newly introduced Phase to Amplitude Approximation (PAA) method are proposed. Finally, a reflectarray antenna is designed and fabricated to have a low sidelobe level and its performance is investigated.
M. Khalaj-Amirhosseini,
Volume 17, Issue 1 (March 2021)
Abstract
Linear and planar antenna arrays are synthesized to have maximum directivity for a specified sidelobe level. The directivity is maximized subject to a given SLL. The beamwidth and the zeros of array factor are studied as well as the directivity. Maximum directivity-arrays are compared through some examples with super-directive, uniform, Dolph-Chebyshev and Riblet-Chebychev arrays to find a complete definition of optimum arrays. Also, the optimum value of n-bar is intuitively found for Taylor arrays.
M. Khalaj-Amirhosseini,
Volume 17, Issue 2 (June 2021)
Abstract
Nonuniform Phased Sampling method is proposed to phase-only synthesize the power pattern of both linear and planar antenna arrays. This method modifies the conventional sampling method which is used for amplitude-phase synthesis. This method is based on assigning suitable phases to the sampling points of radiation pattern in order to reach desired amplitude of currents. Some examples are given to verify the effectiveness of the proposed method for both pencil-beam and shaped beam patterns.
M. Khalaj-Amirhosseini,
Volume 18, Issue 3 (September 2022)
Abstract
Linear antenna arrays are synthesized to have maximum directivity for a specified beamwidth. The directivity is maximized subject to a given beamwidth such as null to null or half power one. The excitation currents are obtained using a matrix equation obtained from the Lagrange multiplier method. The performance of the proposed method is studied by means of some examples. The synthesized arrays have the pre-specified beamwhidths and their directivity is close to the number of elements.
