Open Access

ARTICLE

Automated Synthesis of Wideband Bandpass Filters Based on Slow-wave EBG Structures

Marco Orellana¹, Jordi Selga¹, Paris Vélez¹, Marc Sans¹, Ana Rodríguez², Vicente Boria², Ferran Martín¹

1 GEMMA/CIMITEC, Departament d’Enginyeria Electrònica, Universitat Autònoma de Barcelona, 08193 Bellaterra (Barcelona), Spain.
2 Departamento de Comunicaciones-iTEAM, Universitat Politècnica de València, 46022 Valencia, Spain.

Computers, Materials & Continua 2016, 52(3), 159-174. https://doi.org/10.3970/cmc.2016.052.157

Abstract

This paper is focused on the automated synthesis of wideband bandpass filters operating at microwave frequencies and based on electromagnetic bandgap (EBG) structures. The classical counterpart of such filter consists of a combination of transmission line sections and shunt-connected grounded stubs placed at equidistant positions. By replacing the transmission line sections with capacitively-loaded lines (a kind of EBG-based lines) exhibiting the same phase shift at the lower cutoff frequency and the same characteristic (actually Bloch) impedance, filter size is reduced and the spurious pass bands can be efficiently suppressed. In practice, the loading capacitances are implemented by means of patches, in order to achieve a fully planar filter implementation. The presence of the patches reduces the effective phase velocity of the capacitively-loaded lines, thus providing a slow-wave effect useful for filter miniaturization. Moreover, due to periodicity, such EBG-based lines exhibit wide stop bands, which are used for spurious suppression. Even though such EBG-based filters were previously reported by some of the authors, a systematic synthesis method was not applied for filter design. In this paper, the main aim is to demonstrate the potential of aggressive space mapping (ASM) for that purpose, and it will be shown that such filters can be automatically synthesized.

---

Keywords

---