Design, simulation, and fabrication of a wearable dual-band filter with felt substrate for application in medical systems

In this paper, a wearable dual-band filter is designed, simulated, and fabricated to operate at GPS and Bluetooth telecommunication frequency bands. In this filter, the frequency bands of 1.563-1.678 GHz and 2.4-2.48 GHz are achieved. These two frequency bands are widely used in the design of telecommunication-medical systems. The textures are generally used in place of conventional dielectric for the design of wearable devices. These include texture, denim, wool, and felt. In this filter, a felt substrate with dielectric constant 1.3 and 2 mm height is used. In this paper, CST Microwave Studio 2019 full-wave software is used to simulate all structures. The final dimensions of the resonators of this filter are 6 × 2 cm2 or 0.25 × 0.03 λg2 at 1.57 GHz. The filter was then fabricated to verify the simulations performed. The results of the measurement of the characteristics of this filter as well as the simulation results are in good agreement with each other.