Tunable Front-end Design with a Dual-band Antenna for Small Cellular Devices
Strict power and form factor requirements of miniaturized IoT wearable devices have introduced severe challenges in equipping them with multi-band cellular IoT connectivity. The antenna front-end renders the primary obstacle since supporting narrow and multi-band cellular connectivity requires a range with extensive coverage and high selectivity. This fact, in turn, would require a larger antenna and multiband filtering. Recently, high-Q tunable antennas have shown great potential in eliminating multiband filtering. However, their coverage and tuning range in small dimensions has proved to be inadequate to present a global coverage. This paper proposes a novel tunable antenna front-end architecture to address this problem. The proposed architecture benefits a dual-band, high-Q and tunable antenna in conjunction with tunable filters to cover a large variety of LTE-M bands in the resolution of 700 MHz to 2155 MHz including bands: 3, 4, 12, 13, 17 and 20. The design and implementation are discussed in detail, and related measurements are presented to prove the tuning capability.