Modeling the effect of bend radius on the performance of a conformal dual-band mm- wave patch antenna array Ashraf Umar 1 , Mohamed Y. Abdelatty 2 , Abdullah Obeidat 2 , Emuobosan Enakerakpo 2 , Mohammed Alhendi 2 , and Mark. D. Poliks 2 1 Dept. of Electrical and Computer Engineering, State University of New York at Binghamton, USA 2 Dept. of Systems Science and Industrial Engineering, State University of New York at Binghamton, USA Abstract There is growing interest in the use of additive manufacturing for the fabrication of RF devices due to fast prototyping capabilities and the use of less material as opposed to traditional fabrication techniques. In addition to the previously mentioned advantages, the aerosol jet printing method in particular allows for the conformal printing of RF components. This work models the effect of the bend radius on the return loss and radiation pattern of a dual-band (28 GHz and 39 GHz) mm wave patch antenna array design that will be aerosol jet printed. The antenna is modeled on a 5-mil thick flexible substrate (PET) and the simulation is run from 27 GHz to 40 GHz using HFSS. The return loss and radiation pattern results of the antenna are compared for various bend radii (0.25 in to 2 in) of the conformal surface the antenna is to be printed upon. Simulation results show a maximum frequency deviation of about 400 MHz on the return loss for the low (28 GHz) frequency band of the antenna when it is bent from a bend radius of 0 in to 2 in. Keywords dual-band, mmwave, array, patch antenna, additive manufacturing, HFSS I. INTRODUCTION The Internet of Things (IoT) is a collection of devices that are connected using standard based communication protocols for the purpose of sharing data [1]. There is a growing demand to connect more devices to the IoT networks thereby increasing the total amount of data that needs to be transmitted. As a result, there has been growing interest in 5G mm-wave technology because it allows for high data rate and low latency communication [2]. Printed flexible electronics are among the components that have seen an increased demand to include in the IoT application space [3]. These devices require antennas for communication and hence the study and design of antennas is important to achieve IoT connectivity. Some factors considered in choosing antennas for flexible electronics IoT applications include conformability, flexibility, and durability[3]. These antennas can be fabricated using conventional techniques such as electroplating or additive manufacturing such as Aerosol Jet Printing (AJP) or screen printing. Additive manufacturing offers the advantage of fast prototyping and low-cost fabrication however their performance is not as good as those of conventionally manufactured antennas especially at high frequencies due to issues such as surface roughness, uneven trace profiles and non- uniform edges which lead to decreased antenna gain and impedance mismatches [3]. Planar antenna arrays can be used to improve on this decreased gain and directionality and allow for beam forming and beam steering. They also have the advantage of a low profile as compared to reflector or horn antennas [4]. Patch antennas are planar antennas that are low cost, compact in size and easy to design and hence are good candidates for mm-wave applications [5]. In this paper, we design a two-element dual-band mm-wave planar patch antenna array and investigate the effect of the bend radius on the return loss and gain of the antenna at the two design frequencies of 28 GHz and 39 GHz. II. SINGLE ANTENNA DESIGN The antenna is designed on a 127 µm thick PET substrate with a dielectric constant, Dk of 2.9 and loss tangent of 0.008. The conductor is silver nanoparticle ink with conductivity of 7812500 S/m. Thickness of the conductor used is 10 µm to minimize losses associated with the skin effect. Design frequencies are 28 GHz and 39 GHz. The antenna comprises of a square patch with L-shaped slots near the edges to allow for the excitation of distinct frequencies [6]. An approximate equation for calculating the length of the patch for 28 GHz operations is   =  0 2  �   (1) Where   is the resonant frequency of the patch and   and   are the effective length of the patch and the effective permittivity of the substrate respectively. Fig. 1. show a top and front view (cross section) of the antenna. IMAPS 2022 - 55th International Symposium on Microelectronics | October 3-6, 2022 | Boston, MA USA 000094