High Performance Miniature Antennas for Hand-Held Personal Communication Systems (PCS)

Capable of interference rejection, this antenna is well suited for hand-held PCS. In its basic form, the antenna consists of a pair of vertical quarter wave dipoles separated by a fraction of a wavelength. Initially only one dipole is engaged, for omni directional coverage. The second dipole is also engaged, when higher gain and/or interference rejection is required. The excitation phase of one of the dipoles can be continuously varied with respect to the other to vary the combined radiation pattern until acquisition of the received signal is achieved above threshold, and then the phase shifting stops until acquisition dropout is approached, after which it resumes. In our approach, the desired radiation pattern just has to be a satisfactory combination of received signal gain and interfering signal rejection, to achieve acquisition above threshold. The proposed scheme leads to low-cost and small size implementation. This technology promises widespread, affordable access to high bandwidth hand-held PCs for the Electronic Battlefield and commercial uses, such as mobile communications where mutual interference signal rejection capability is important. Potential commercial benefits are reduction of mutual interference between cellular phone, PCS users and other outside users.