A new class of 3-D filter/antenna integration with high quality factor and high efficiency

A novel approach to integrate high-Q 3-D filters with highly efficient slot antennas is presented in this paper. This technique allows for seamless integration of 3-D filters and antennas, which can greatly improve the antenna efficiency and significantly reduce the form factor of RF front ends. A prototype four-pole chebyshev cavity filter integrated with a slot antenna is demonstrated in X band. The center frequency and fractional bandwidth of the filter/antenna system are 9.96 GHz and 6.0%, respectively. Due to the high Q factor (~1,000) of the cavity resonator, the efficiency of the filter/antenna system is measured to be 89%, compared with the measured S₂₁ of -0.5 dB (89%) for an identical filter. This means a near 100% efficient slot antenna is achieved within this integrated filter/antenna system. The measured impedance matching, efficiency, gain, and radiation pattern closely agree with simulation results.