A dynamically reconfigurable antenna system for an RFID (Radio Frequency Identification) reader/encoder includes a plurality of antenna elements; and a mechanism constructed and adapted to dynamically and selectively configure said plurality of antenna elements during operation thereof. The antenna elements may be arranged in a pattern of conductive areas, and each antenna element is switchably connectable to ground or to a transmission line connectable to the RFID reader/encoder. Each antenna element may be square, rectangle, circular, or diamond shaped. The antenna elements may located on an inner layer of the multi-layer printed circuit and wherein regions above the antenna elements are a dielectric layer or a slot aperture. The antenna system may be incorporated into an RFID encoder/reader.