Error Vector Magnitude, Intermodulation, and Radiation Characteristics of a Bandwidth- and Pattern-Reconfigurable Antenna

This letter presents the error vector magnitude (EVM), intermodulation (IM), and radiation performances of a reconfigurable antenna capable of varying its bandwidth between 3.4-3.6 and 3.1-3.9 GHz bands, and steering its main beam into three directions pertaining to \theta \in \lbrace -30^{\circ },0^{\circ },30^{\circ }\rbrace and \phi \in \lbrace 0^{\circ }\rbrace for each band. Two parasitically coupled reconfigurable layers located on top of a driven antenna used in conjunction with a reconfigurable feed layer employing p-i-n diode switches enable a concurrent configuration of an impedance bandwidth and a radiation pattern. The maximum realized gain of \sim9 dB has been achieved for all modes of operation as shown by measurements and simulations. Measurements indicated less than -25 dB (5.6\%) EVM for input powers up to 30 dBm and revealed that the combined effects of loose solder joints and large nonlinear response of p-i-n diodes are the main factors resulting in passive IM products.