Millimeter Wave Filter Design with Suspended Stripline
Abstract
Planar and integrated microwave circuitry for application in radar and guidance systems is predominantly based on the microstrip transmission medium. Due to high microstrip losses with increasing frequency, lower-loss media are required for frequencies at K sub c -band (30GHz) and above. These higher frequencies are coming into increased use for higher target resolution and improved security. The important alternative microwave transmission media which preserve the advantages of planar printed circuit forms are the finline and shielded suspended-substrate systems. Of those two media, the finline has had extensive application and theoretical investigation. The shielded suspended- substrate stripline (SSL) has the potential for very low transmission loss since, in its quasi-TEM propagation mode, the current densities are very low due to its additional air gap, relative to microstrip. The SSL is at present a developmental system, and well-verified design rules are not yet available for it. A number of empirical formulas for the computation of the SSL transmission line parameters have been published in the literature, but the validity and accuracy of these formulas is not known. At present, essentially no information is available for discontinuities such as capacitive gaps or angles in the medium. The series capacitive gap is of particular interest in that a useful microwave filter can be built using resonator sections coupled by series capacitive gaps. Keywords: Microwave circuits.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1989
- Accession Number
- ADA219582
Entities
People
- Anastasios K. Kotronis
Organizations
- Naval Postgraduate School