A Novel Additively 4D Printed Origami-inspired Tunable Multi-layer Frequency Selective Surface for mm-Wave IoT, RFID, WSN, 5G, and Smart City Applications

This paper presents a novel 4D printed tunable frequency selective surface (FSS) utilizing a multi-layer mirror-stacked “Miura-ori” structure that can be applied in numerous mm-Wave, IoT, RFID, WSN, 5G, and smart city applications. The prototype was fabricated with fully additive hybrid (3D and inkjet) printing processes to realize a flexible two-layer substrate with conductive traces on both top and bottom. The proposed multi-layer/multi-material manufacturing process features very significant strength improvement over paper-based origami structures, while enabling the realization of increasingly complex “morphing” designs that would be otherwise difficult to fabricate using traditional paper-based substrates. The proof-of-concept prototype demonstrates great frequency tunability, angle of incidence (AoI) rejection, and significantly improved insertion loss performance over simpler single-layer Miura-based designs as well as an operability up to much higher mm-wave frequencies up to at least 28 GHz.

I. Introduction

In recent years, frequency selective surfaces (FSSs) have been playing an essential role in emerging technologies such as the internet of things (IoT) [1], [2], RFID [3], wireless sensor network (WSN) [4], 5G [5], [6], smart city [7], etc. To enable effective operability of practical systems in cluttered frequency bands with common time-changing interference, reconfigurable FSSs have to be utilized in order to filter different interfering frequency bands on-the-fly. The common methodology to realize a tunable FSS is to integrate active components such as p-i-n diodes [8], MEMS switches [9], or varactors [10] within the FSS elements. Active components can be responsive and relatively easy to control. However, at the same time, they can be expensive, fragile, and hard to fabricate, limiting the performance and scalability of the reconfigurable FSS.