A Novel Multiband Directional Antenna for Wireless Communications

A novel multiband patch antenna with unidirectional radiation is proposed by integrating resonators in the design. The multiple frequency bands are achieved based on a coupled resonators network. The topology and design methodology are detailed. The patch not only works as the last-order resonator of the network, but also as the radiating element. Using this approach, multiple bands can be achieved without changing the shape of the radiation element. In addition, the operation bands can be adjusted by adjusting the coupling between the resonators. In this work, the four bands are designed at 4.6, 5.05, 5.8, and 6.3 GHz as a proof-of-concept. The prototype is fabricated and tested, and measured results agree very well with the simulations, showing an excellent performance in terms of impedance matching, radiation patterns, gains, and cross-polarization discrimination.