Enhanced Coupling Values in Coupled Microstrip Lines using Metamaterials
Abstract
In this paper, we show how metamaterials can be used to enhance the coupling values of microstrip directional couplers. Coupling between regular coplanar microstrip lines, in fact, is limited, due to the small ratios between the characteristic impedances of even and odd TEM modes supported by the structure. The broadside configuration or the employment of an overlay are often utilized to overcome this limitation, leading, however, to more bulky components. On the other hand, the employment of metamaterials with a negative real part of the permittivity is able to increase the coupling values, while keeping the profile of the structure very low. A quasi-static model of the structure is developed and physical insights on the operation of the proposed component and on the role of the metamaterial loading are also given. Simple design formulae derived through a conformal mapping technique are presented and validated through proper full wave numerical simulations.
Keywords
Coupled lines, microstrip lines, metamaterialsPersistent identifier
http://hdl.handle.net/11012/57192Document type
Peer reviewedDocument version
Final PDFSource
Radioengineering. 2008, vol. 17, č. 2, s. 56-60. ISSN 1210-2512http://www.radioeng.cz/fulltexts/2008/08_02_056_060.pdf
Collections
- 2008/2 [22]