چكيده به لاتين
Abstract:
A Diplexer is a three-port network which divides input signal into two channels with two different frequency bands. A Diplexer is actually a simplified multiplexer and is usually designed with low pass, band pass and high pass filters or a combination of them. A Diplexer separates receiver and transmitter channels from each other. Close attention should be paid to isolation, insertion loss and return loss while designing diplexers. Another important design factor of diplexers is the ratio of frequency channels.
In this thesis, we propose a design for diplexers which employs two Branch line Hybrid and third order simple Hairpin filter (Branch line hybrids can be Dual band or wide band). This design was implemented with Microstrip lines. The advantage of our proposed design is its simplicity and generality in arbitrary frequencies in comparison to other designs in this field. Also due to utilization of Branch line hybrids and combination of powers, Much better isolation is achieved and insertion and return loss are minimized.
The proposed method is designed and programmed in MATLAB and then then simulated and Optimized in ADS and HFSS. To verify this design, an instance of our proposed diplexer was built with two nearly equal frequency bands and the results were measured and compared to previous works in this field. The practical results completely confirm with simulated results and corroborate the validity of our design.
Keywords: Diplexer, Microstrip, Isolation, Dual Band Branch Line, Wide Band Branch Line
