Reduced Loss and Prevention of Substrate Modes with a Novel Coplanar Waveguide Based on Gap Waveguide Technology

Carlos Biurrun-Quel; Jorge Teniente; Carlos Del-Río

doi:10.3390/s23062909

Reduced Loss and Prevention of Substrate Modes with a Novel Coplanar Waveguide Based on Gap Waveguide Technology

Sensors (Basel). 2023 Mar 7;23(6):2909. doi: 10.3390/s23062909.

Authors

Carlos Biurrun-Quel^{1

2}, Jorge Teniente^{1

2}, Carlos Del-Río^{1

2}

Affiliations

¹ Antenna Group, Department of Electrical, Electronic and Communications, Public University of Navarra, 31006 Pamplona, Spain.
² Institute of Smart Cities, Public University of Navarra, 31006 Pamplona, Spain.

Abstract

The Gap Waveguide technology utilizes an Artificial Magnetic Conductor (AMC) to prevent the propagation of electromagnetic (EM) waves under certain conditions, resulting in various gap waveguide configurations. In this study, a novel combination of Gap Waveguide technology and the traditional coplanar waveguide (CPW) transmission line is introduced, analyzed, and demonstrated experimentally for the first time. This new line is referred to as GapCPW. Closed-form expressions for its characteristic impedance and effective permittivity are derived using traditional conformal mapping techniques. Eigenmode simulations using finite-element analysis are then performed to assess its low dispersion and loss characteristics. The proposed line demonstrates an effective suppression of the substrate modes in fractional bandwidths up to 90%. In addition, simulations show that a reduction of up to 20% of the dielectric loss can be achieved with respect to the traditional CPW. These features depend on the dimensions of the line. The paper concludes with the fabrication of a prototype and validation of the simulation results in the W band (75-110 GHz).

Keywords: coplanar waveguide; electromagnetic bandgap; gap waveguide; mmWave; substrate modes; transmission line theory.

Abstract

Grants and funding