Flexible Trident Foam Antenna With Narrowband Characterization for NB‐ IoT and LTE Cellular Communications

Abstract

With the rapid expansion of LTE (Long Term Evolution) cellular and IoT (Internet of Things) enabled systems, there is a growing demand for compact, low‐cost and flexible antennas. Present antennas are commonly built using rigid substrates which are not suitable for flexible applications and offers more signal reflection rather than far field radiation. Proposed work addresses this demand by a lightweight foam substrate based flexible antenna that operates at 1.74 GHz LTE‐band 4 and additional 1.4 GHz LTE—band 11 to support (Narrow Band) NB‐IoT applications. A trident shaped antenna built using foam with 1.2 mm thickness and permittivity of 1.15. Stagewise analysis in terms of electrical and geometrical is focused to improvize current distribution, radiation characteristics with lesser reflections. Gain and radiation efficiency of about 3.9 dB and 90.6% is achieved with the final stage antenna, with an impedance bandwidth of 570 MHz. Simulated results are validated with the measured results using vector network analyzer and anechoic chamber. Simulated and measured return loss is about −42.3 and—31 dB respectively. To verify the flexibility and wearability of the antenna, conformal and SAR simulations are performed and analyzed for the real time deployment in flexible IoT and LTE cellular applications.