@conference {18_URSI_PABLO_SANCHEZ, title = {Conformal Patch Array Antenna with Switchable Omnidirectional or Sectorial Coverage at 3.5 GHz}, booktitle = {Simposium Nacional URSI 2018}, year = {2018}, month = {September}, abstract = {A circularly conformal array antenna with beam steering capabilities as well as omnidirectional performance in S-band is presented. The single radiating elements are formed by double stacked microstrip patches placed on the planar faces of an octagonal supporting structure fabricated with a 3D printer. An eight-way tunable feeding network in microstrip technology is designed, manufactured and integrated into the conformal structure in order to excite the array elements. Novel tunable T-junctions based on PIN diodes are proposed to form the tunable feeding network. This novel T-junction allows a splitting configuration with uniform distribution to the two output ports, or a switching mode to deliver the signal to either output port. In all T-junction operation modes, a good input matching performance is achieved. The tunable feeding network is integrated into the conformal antenna and digitally controlled by a microcontroller Arduino UNO. A total of 29 states, grouped in 6 modes with a global matching bandwidth of 17.2\% can be selected. An omnidirectional radiation as well as beam steered directional patterns (covering 360 deg) can be electronically selected. The proposed antenna is able for future 5G terrestrial communications in the 3.5 GHz IMT range.}, author = {P Sanchez-Olivares and P P Sanchez-Dancausa and J L Masa-Campos and M Iglesias-Menendez-de-la-Vega and E Garcia-Marin} }