Abstract
This article presents the study and numerical analysis of three new broadband filters such as broadband bandpass filters based on broadside edge coupled coplanar waveguide with double-sided parallel step impedance resonators (SIRs) at optical frequency bands. The designed three broadband filters can perform effectively with a lower than 1 dB pass-band insertion loss. The basic transmission line characteristics of the broadside coupled CPW for the even-mode and odd-mode excitations are determined by using the quasi-static conformal mapping technique. These three filters are designed within a higher impedance transmission line section inserted between two lower impedance transmission line sections using cross-coupled resonance conditions. Among all these three filters, filter (III) gives better performance at optical frequencies, which is designed based on the design of the other two initial filters (I), (II). Due to their well-balanced characteristics, these filters provide both broadband operation and ultra-compact circuit size and are useful in the design of nanoscale subwavelength wireless networks.