الفهرس | Only 14 pages are availabe for public view |
Abstract Microwave low pass filters are essential devices in RF wireless communication systems to remove noise, harmonics and other spurious signals.For these circuits, size compactness and high power attenuation levels throughout a broad stopband spectral range are desired properties to efficiently accomplish this task. Different techniques have been investigated i.e. using resonators, shaped transmission lines, and defected ground structures to achieve miniaturization of microwave filter. In this thesis, a new design for compact microstrip LPF with sharp cutoff characteristics is introduced. Defected ground structure(DGS)and defected microstrip structure(DMS)have been used to obtain wide stopband. The proposed filter is composed of two new arc shaped DGS units in the ground plane and a shaped microstrip line where stub and inset feed matching techniques is attached to enhance the pass band characteristics. This structure allows sharp cutoff frequency response and high harmonics suppression. Furthermore, it provides compact filter size without the need for cascading periodic DGS structures. On the other hand, duplexer is often the key component of the transceiver for modern wireless or mobile communication systems. It allows two way radios to operate in a full duplex manner. |