A Compact Diplexer Based on Low Profile Multilayer FSS Filters for Ultra-High Data Rate Point to Point Wireless Communication System

Abstract

Abstract-In this paper, we propose the design of multilayer frequency selective surfaces (FSS) waveguide band-pass filters (WBPF). The WBPFs are designed to operate at two different frequency channels, respectively 71-76 GHz (Rx) and 81-86 GHz (Tx). The cross section surface of the FSS is imposed by the WR12 waveguide rectangular section's dimensions. The WBPFs are inserted symmetrically in a T-junction waveguide to design a compact diplexer. This is a basic component developed for an efficient integration in the future E-band millimeter-wave transceiver. The multilayer FSS structure uses only non-resonant sub-wavelength unit cell elements; metallic patch and slot. To reach high channel isolation (≈ 70 dB) a seven order filter was required. Hence, each filter is composed of 13 capacitive and inductive metallic FSS spaced by 12 ultra-thin dielectric substrate layers. The dielectric material is Rogers Ultralam 3850 (Liquid Crystalline Polymer; LCP circuit material). The filter's overall thickness is < λ/4. The numerical studies have been performed using finite element method simulator (HFSS) and CST Studio Suites Tools. The experimental validation has been also done in the X band frequency by developing a fifth order FSS WBPF. Good agreements between simulated and measured results are obtained.

Compact 60 GHz low‐temperature cofired ceramic filter with quasi‐elliptic bandpass response

“…On the basis of the commercial LTCC technology and multilayer structure, this paper developed an alternative quasi‐elliptic filter at 60 GHz by combining dual‐mode SIW cavities with a shielding cavity. The proposed structure was inspired by the concept of a waveguide filter based on a frequency selective surface (FSS) [10–12], in which a rectangular waveguide was combined with FSS cells to realise waveguide filters. These waveguide filters published in [10–12] have frequency responses similar to those of the embedded FSS structures.…”

“…The proposed structure was inspired by the concept of a waveguide filter based on a frequency selective surface (FSS) [10–12], in which a rectangular waveguide was combined with FSS cells to realise waveguide filters. These waveguide filters published in [10–12] have frequency responses similar to those of the embedded FSS structures. However, because of the complex FSS structures, designing the waveguide filters at 60 GHz is challenging.…”