Pattern-Reconfigurable Cavity-Backed Antenna Based on Radiant Metal Blocks

In this letter, a design method for the reconfigurable radiant metal block antenna with beam switching is proposed. The pattern-reconfigurable antenna is realized using the concept of mismatch in filter theory. The positive intrinsic negative (PIN) diodes are employed to change the characteristic current mode of the radiant metal block to achieve the switching of the matched or mismatched state between the block and the resonant metal cavity. Based on this feature, a second-order reconfigurable cavity antenna is designed by placing reconfigurable metal blocks around the resonant metal cavity. The designed antenna is capable of covering a 360<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{\circ }$</tex-math></inline-formula> area range. Not only can different radiation patterns be designed for switching, but also it is ensured that the second-order filtering characteristics are maintained when switching beams. For validation, a six-beam switchable metal block cavity filtering antenna is fabricated and measured. The bandwidth of the designed antenna is 4.8% and the radiation pattern can be controlled to switch from 0<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{\circ }$</tex-math></inline-formula> to 360<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{\circ }$</tex-math></inline-formula> in steps of 60<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{\circ }$</tex-math></inline-formula>. The nice consistency between the measured and simulated results validates the proposed design methodology.