Printed GNSS and Bluetooth Antennas Embedded on Flexible Low Loss Substrates for Wearable Applications

Abstract

This paper presents Global Navigation Satellite System (GNSS) F-type and Bluetooth (BT) L-shaped antennas printed on flexible low loss substrate materials for smartwatch applications. The proposed printed antennas were designed along with the wristband of a smartwatch device with the main purpose of improving their electrical performance by using a new low loss polymer material and locating the antenna on the wrist strap. The antenna performances were simulated using CST Microwave Studio, and the prototypes were measured in a Satimo StarLab anechoic chamber. Silver printing and injection molding technologies were successfully utilized for fabricating new SEBS materials (styrene-ethylenebutylene-styrene) in wearable devices. The SEBS materials improved the radiation efficiency of the antennas by 1.6 dB for the GNSS and 2.2 dB for the BT over the previously used TPU (thermoplastic polyurethane) materials. The overmolded printed and hybrid integrated discrete antennas produced added-value for electronics fabrication thanks to its flexible and seamless integration technique. In addition, it is a low-cost mass manufacturing method. The research opens new perspectives for product definitions with a flexible, low loss material that enables better antenna performance.

The integration of electronic circuits in plastics using injection technologies: a literature review

“…Wimmer et al [80] developed a capacitive touch panel for use in an automotive interior, moreover, the author concluded that the printed conductive structures must be optimized for the forming process to achieve and maintain the highest possible electrical conductivity. Printed antennas for wearable applications were shown by Gbotemi et al [81]. Tuomikoski et al [82] demonstrated indoor air quality monitoring and red-green-blue (RGB)-LED luminaire devices that included both printed functionalities and IM integration as illustrated in figures 17 and 18.…”

A Study on Over-Molded Copper-Based Flexible Electronic Circuits

“…Wimmer et al [ 11 ] concluded that printed conductive structures must be optimized for the forming process to achieve and maintain the highest electrical conductivity possible. O. M. Tuomikoski et al [ 12 ] demonstrated indoor air quality monitoring and red-green-blue (RGB) luminaire devices with both printed and injection-molded parts. In addition to this, some researchers have expressed interest in examining the impact of the process on different electronic packages, flexible foil materials, metallization, assembly methods, and mold shapes to determine the effect of plastic materials on microsystems [ 13 , 14 , 15 , 16 , 17 ].…”