Research Of Asymmetric Coplanar Waveguide Filter With Defected Ground Structure

Microwave planar circuit filter is widely used in microwave technology, as it can be machined with etching technology, be small scale and can be integrated easily with passive circuit elements. CPW (Coplanar waveguide) transmission lines have some merits compared to other microwave planar transmission line which extensively made in microwave filter. In order to make use of CPW flexibly, people design its two slot widths as unequal, which became as ACPW (Asymmetric coplanar waveguide), so there is one more parameter available for optimizing. In the meanwhile, etching some figure such as DGS (defected ground structure) in CPW metal ground can improve filter performance and decrease circuit size, which made ACPW filter with DGS have important research significance.Different kinds of electromagnetism and electromagnetic simulation software benefited from the stringent research of RF devices applications. Agilent Technologies is the famous producer and supplier of simulation software and measuring devices.2008, Agilent introduced a new design software EMPro which can be used to analyze the antenna, high speed IC packaging, RF/microwave components, etc. This paper's simulation tool is genuine EMPro2010.The main content and innovative points of this paper are as follows:1. This paper introduced some planar transmission line such as CPW, ACPW first, then DGS and filter theory briefly, which do help to design ACPW filter with DGS.2. Use EMPro2010 to do quantities of simulation about excitation setup of CPW transmission line and ACPW transmission line. Besides, analyzed the simulation results and attained the rule of excitation setup of CPW and ACPW in EMPro2010.3. Simulated CPW filter with DGS and ACPS filter with DGS, the results validated the excitation setup rule of CPW. Based on the two filters, this paper designed a new ACPW filter with ADGS(ACPW-asymmetric DGS), and made compare to CPW-DGS filter,ACPW-DGS filter as well. At last, manufactured and tested the three filters, the test results agree well with the simulation results.