Highly selective and tunable microwave photonic filter using parallel Fabry-Perot filters for universal mobile telecommunications system noise and interference suppression

The authors propose a highly selective and tunable microwave photonic filter based on parallel Fabry-Perot filters with fibre Bragg gratings for delay. The filter is suitable for noise and interference suppression in universal mobile telecommunications system (UMTS) base stations. Simulation results demonstrate the feasibility of these filters in UMTS applications, and also show flexibility in their frequency response. Tunability of the filter has been employed for UMTS channel selection and grating length has been tuned in order to achieve appropriate delay. The filter provides a very high selective performance (in the frequency range of 1937-1976-MHz and a very high-quality factor of 494) with very high sidelobe suppression (>;36-dB) in the stop band with lesser number of components. Tunability and reconfigurability of the proposed filter was obtained by changing the grating length. In this way, easy implementation of simple, compact and cost-effective filter has been demonstrated.