Electromagnetic-Thermal Analyses of Distributed Antennas Embedded into a Load Bearing Wall

TL;DR

This paper investigates embedding antennas into load-bearing walls to enhance indoor cellular connectivity without sacrificing thermal insulation, providing analytical models, optimization, and empirical validation of the approach.

Contribution

It introduces a novel signal-transmissive wall design with embedded wideband antennas, balancing electromagnetic transmission and thermal insulation in low-energy buildings.

Findings

Electromagnetic transmission improved by 22 dB across 2.6-8 GHz.

Embedded antennas do not compromise thermal insulation.

Analytical and empirical models validate the design's effectiveness.

Abstract

The importance of indoor mobile connectivity has increased during the last years, especially during the Covid-19 pandemic. In contrast, new energy-efficient buildings contain structures like low-emissive windows and multi-layered thermal insulations which all block radio signals effectively. To solve this problem with indoor connectivity, we study passive antenna systems embedded in walls of low-energy buildings. We provide analytical models of a load bearing wall along with numerical and empirical evaluations of wideband back-to-back antenna spiral antenna system in terms of electromagnetic- and thermal insulation. The antenna systems are optimized to operate well when embedded into load bearing walls. Unit cell models of the antenna embedded load bearing wall, which are called signal-transmissive walls in this paper, are developed to analyze their electromagnetic and thermal insulation properties. We show that our signal-transmissive wall improves the electromagnetic transmission compared to a raw load bearing wall over a wide bandwidth of 2.6-8 GHz, covering most of the cellular new radio frequency range 1, without compromising the thermal insulation capability of the wall demanded by the building regulation. Optimized antenna deployment is shown with 22 dB improvement in electromagnetic transmission through the load bearing wall.