Design Of Lossy Microwave Filters

Zahriladha, Zakaria (2010) Design Of Lossy Microwave Filters. PhD thesis, University of Leeds.

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This thesis presents novel techniques for the design of microwave filters which allow for the realisation of lossy filter responses equivalent to loss-less filter responses, although at an increased insertion and return loss. Hence, the filter can be designed with low Qu resonators, which will significantly contribute to the reduction of its physical volume. The first design was developed using coaxial technology to produce a third-order Chebyshev band-pass filter. The filter development began with the low-pass prototype as a starting point. The resulting filter was structured from a combination between the combline resonators and coaxial lines. The second and third designs were developed using a completely different medium of realisation, i.e. based on Substrate Integrated Waveguide (SIW) technology. The concept of SIW was formulated from a conventional rectangular waveguide by a set of design rules. The second filter produced a three-stage band-pass filter with Chebyshev characteristic, whilst the third design produced a threestage band-stop filter with an inverse Chebyshev characteristic. Thus, the systematic filter development for the band-stop filter was initiated from the high-pass prototype. Both band-pass and band-stop SIW filters were constructed from the combination between SIW resonators and microstrip lines. In order to validate the concept, all designs were manufactured and measured. The experimental results show excellent agreement with the simulated performance. The main benefit of the coaxial resonator filter is post-manufacturing tuning capabilities, whilst the SIW resonator filter has the advantage of its small physical volume, as well as being able to easily integrate with other planar devices at a low cost and using standard printed circuit board process. This new class of microwave filters is considered suitable for applications, particularly where the increased loss can be tolerated and the reduction of physical volume is very important, such as in the case of input multiplexer of a communication satellite.

Item Type: Thesis (PhD)
Uncontrolled Keywords: Microwave filters
Subjects: T Technology > T Technology (General)
T Technology > TK Electrical engineering. Electronics Nuclear engineering
Divisions: Library > Tesis > FKEKK
Depositing User: Azman Amir
Date Deposited: 10 Oct 2012 06:47
Last Modified: 28 May 2015 03:41
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