Multifunctional Radio Frequency Device With Integrated Dual-Polarized Antenna, Filters, and Power Combiners for Base-Station Applications

This letter proposes a multifunctional radio frequency (RF) device that integrating filters, antennas and power combiners for base station applications. The design mainly consists of a pair of driven patches, a parasitic patch and two pairs of transmission lines with open-circuit stepped-impedance resonators as the feeds. This design employs the TM₀₀ mode of a driven patch to transmit energy and form a fourth-order low-pass filter by utilizing the opened circuit stubs, while the TM₁₀ mode of the patch to form a frequency band for radiation. The proposed device exhibits filtering performance with high roll-off at the upper and lower band edges when it works as an antenna, and when it works as a low-pass filter, it has a cutoff frequency at around 1 GHz with a low insertion loss of 0.6 dB and a wide stopband up to 2.5 GHz. For demonstration, the proposed multifunctional device is implemented and verified. The proposed multifunctional device could be used to feed multiple antennas with different operating bands in series, resulting in a miniaturization and high integration of the RF frontend system.