A Post-Fabrication Tuning Method for a Varactor-Tuned Microstrip Filter using the Space Mapping Technique

The RF (radio frequency) and microwave filter is of great importance in the most of the microwave applications which are widely used in broadcasting radios, televisions, radar techniques, telecommunications and satellite applications. Most of the microwave devices contain microwave filter blocks for transmitting and receiving Megahertz to Terahertz frequency band signals. The technologies in the fields of materials, fabrication, design method and electromagnetic analysis are developing quickly in recent years for RF applications. This thesis focuses on an important topic in microwave filter applications, post-fabrication filter tuning. Post-fabrication tuning processes become more and more important with the development of microwave applications and the requirement of stringent filter performance. A fabricated filter often gives very different performance compared to software designed and simulated models due to the fabrication and material tolerances. The post-fabrication tuning process aims to adjust tuning components implemented with the filter to make the filter give the expected performance. The tuning process is traditionally performed by expert technologists with strong filter knowledge and tuning experience, and it is time consuming and expensive in labor costs. Much easier, automated and accurate post-fabrication filter tuning approaches are necessary. In this thesis, the basics of microwave filters, tuning techniques and space mapping techniques are discussed in detail. A novel post-fabrication tuning method that exploits the space mapping technique to directly make tuning decisions is first proposed. The tuning theory and procedures are given in detail. An application of the proposed method to directly determine the tuning voltages of a fabricated 4-pole varactor diode tuned microstrip combline filter with a center frequency of 1 GHz and an absolute bandwidth of 200 MHz is presented. In the proposed application, implicit space mapping is exploited to map the circuit based coarse model and the capacitance values of the varactor diodes of the fabricated filter. The method is shown to be accurate and efficient in which as long as an accurate mapping is established, all the tuning decisions can be directly made exploiting the fast coarse model without further testing and tuning of the fabricated filter.

Name thesis:degree_name

Master of Applied Science (MASc)

Level thesis:degree_level

Master's

Discipline thesis:degree_discipline

Engineering - Electronic Systems

Grantor dc:publisher

Faculty of Graduate Studies and Research, University of Regina

Year dc:date.issued

2015

Author dc:creator

• Li, Song

Advisor dc:contributor.advisor

• Laforge, Paul

Committee members dc:contributor.committeemember

• Zhang, Lei
• Paranjape, Raman

Language dc:language.iso

en

DOI

https://doi.org/10.82465/3873

OAI identifier oai:identifier

oai:uregina.scholaris.ca:10294/6551