الفهرس 
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Abstract
The rapid development of the advanced RF/Microwave wireless communication systems has generated an increasing research interest in performance improvement and size miniaturization of the devices. The main objective of this thesis is to introduce new designs for compact high selective microwave filters, compact full duplex Tx/Rx antennas with high isolation which are considered as the main design targets in any high performance wireless system. In the first part, a new design for LPF with stringent requirements such as high performance, small size, light weight, and low cost is introduced. The filter is based on stepped impedance resonator (SIR), defected microstrip structure (DMS), DGS, and surface mount capacitor techniques. The filter is fabricated on F4B-2 substrate with relative dielectric constant 𝜀𝑟=2.65. The filter design is performed using CST- Microwave Studio software and the filter equivalent circuit is derived using ADS2006A software. The scattering parameters (|𝑆11| and |𝑆21| ) of the fabricated filter are measured using Rohde & Schwarz ZVL20 Network Analyzer. The filter exhibits sharp cut off frequency which equals 1.7654 𝐺𝐻𝑧 and very low insertion loss of about 0.15 𝑑𝐵. In addition, it has compact size of (20×16 𝑚𝑚2). In the second part, A compact full duplex Tx/Rx patch antenna using gear patch antenna and two different size omega shaped DGSs is presented. The two DGSs construct two band pass filters at the two input ports of the antenna. The use of gear patch with the two BPFs can be simply tuned to the desired uplink and downlink frequencies by scaling the size of the reference omega shaped DGS at the two ports. The behavior of the antenna is explained with the help of parametric studies. A high isolation more than 35 dB is achieved by optimizing the dimensions of the proposed antenna which makes it attractive for practical applications.