الفهرس 
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Abstract
A low-loss microwave dielectric material was used to construct a res- onator antenna (DRA), an open resonating structure. Due to their high radiation efficiency, dielectric resonators are excellent choices for antenna applications.DRAs have several advantages over tradi- tional microstrip antennas. The primary goal of this thesis is to de- sign and analyze three different designs of wideband and multiband DRA antennas, namely: Hybrid-Shape DRA, Plus-Shaped DRA with Parasitic Rectangular Elements, and Defected Ground Cross- Shaped DRA. The impedance bandwidth, radiation pattern, return loss, and antenna gains are obtained using an electromagnetic sim- ulator that employs the finite element method. Furthermore, the obtained results are validated by another 3D simulator using a fi- nite integration technique solver. Proposed antennas can be em- ployed in multiband applications, like WLAN, sub-7 GHz, X-band, and Ku-band. The Hybrid-Shape DRA uses the defective structure technique and provides four frequencies bands covering 55.6% with two integrated bandwidths at range (4.04-8.16), 8.6% at range (9.7-
10.64 GHz), 8.1% at range (11.48-12.48 GHz), and 6.9% at range (14.16-15.16 GHz). It achieved a max gain of 5.54 dB at 10.6 GHz. The Plus-shaped DRA with parasitic rectangular elements is pre- sented. Its parasitic elements not only contribute to the excitation of additional frequency bands but also enhance the bandwidth of the operating frequencies, providing two wide bands covering 61.5%, two integrated bandwidths at the range of (4-8) GHz, 10.2%, range (9–10) GHz, 8.5%, range (11–12) GHz, and 20%, three integrated bandwidths with the range (13–16) GHz. Finally, the third design defected ground cross-shaped DRA with a commercially relatively low dielectric constant (ϵr=10.2), fed by a two-level width microstrip
line is presented as a viable solution for the manufacturing process. The performance of the cross-DRA is optimized by studying the impedance bandwidth, radiation pattern, return loss, and antenna gain using an electromagnetic simulator and verified that with fabri- cated and experimentally validated, providing pure four bands (5.41-
7.39), (11.05-12.20), (14.00-15.58) and (16.58-18.36) GHz for S11 ≤
-10 dB, with resonated frequencies (6.4, 11.4, 14.88, and 17.48) GHz which can be employed in multi-band wireless communication appli- cations such as WLAN, sub-7 GHz, X-band, and Ku-band.