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Reflectarray antennas can be considered as quasi-periodic structures in which similar elements locate on periodic grids. In this paper, we compare the reflection phase of elements in the array between the designed value and the practical one. This error is mainly due to the assumption of periodicity in computing the designed element reflection phase. To study this error, we developed a method to obtain...
Reflectarray antennas have been widely used in communications and national defense because of their remarkable advantages such as high gain, low loss, low profile, and etc. In the design of reflectarray antennas, the relation between the reflection phase of every element and its dimensions is usually computed through element simulation with infinite periodic boundary conditions. However, this assumption...
A microwave imaging system for breast cancers using a miniaturized bowtie patch antenna array is presented in this paper. The antenna element was designed with resonant frequency of 2.57 GHz and return loss less than −15 dB. Thirty-six antennas were installed on the walls of the chamber. The back propagation method is used as the imaging algorithm. We demonstrate the capability of the proposed antenna...
In this paper four different reflectarrays, namely, metal-only block reflectarray, waveguide reflectarray, dielectric reflectarray, and traditional microstrip patch reflectarray, are designed as potential solutions for high-gain Terahertz antennas. For the purpose of comparison, all these cases are simulated using full-wave commercial software CST Microwave Studio with the same system configuration...
This paper proposes a reconfigurable microstrip antenna with a tunable radiation beam. The design methodology uses two tunable size parasitic patches placed to the left and right of a probe-fed patch along its H-plane. Each parasitic patch is loaded with a lumped varactor as well as its biasing network, to effectively change its electrical size. Because the radiation beamwidth is controlled by the...
Dielectric reflectarray antennas are studied in this paper as a possible low-loss and low-cost solution for high gain THz antennas. Variable height dielectric slabs are proposed for the reflectarray elements which allow for the use of low dielectric-constant materials for the design. A 3-D printing technology is utilized to fabricate the antenna, and both numerical and experimental results are presented...
The radar based UWB microwave imaging techniques have shown great potential for the localization of embedded dielectric targets in breast phantoms [1], [2]. In practical UWB microwave imaging systems, antennas play a key role in determining the characteristics of the received signals. The antennas behave as spatial-temporal filters as they have to radiate narrow pulses and thus the radiated signal...
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