Small Printed Combined Electric-Magnetic Type Ultrawideband Antenna With Directive Radiation Characteristics

A small printed antenna structure is presented featuring directive radiation patterns over ultrawide frequency band without relying on large antenna dimensions. The antenna comprises virtually two antennas-one electric-type antenna and one magnetic-type antenna-excited simultaneously in close proximity via one feed point. This combination of radiated fields from different types of sources result in directive radiation patterns without increasing antenna sizes as typically observed in antennas using only one type of sources. Two printed prototypes of the combined antenna are fabricated and their measured VSWR and radiation gain pattern characteristics are discussed.