Abstract: A panel antenna suitable for use in cellular communication applications provided with means for mechanically and electrically adjusting the tilt of the antenna beam. Electrical down tilt being achieved by varying the length of a first feed line to a group of dipole pairs. Mechanical down tilting of the antenna beam being achieved by tilting the antenna ground plane and dipole driver assembly with respect to a housing.

Abstract: A coaxial resonator is provided having an outer conductor with top and bottom closures and a substantially central opening through the top closure through which a tubular member forming a center conductor extends. The center conductor also comprises a plunger which is moveable within the tubular member such that the electrical length of the center conductor can be varied to effect tuning of the resonator.The tubular member and the plunger are spaced apart in slidable relationship one with the other and as the bottom end of the tubular member represents essentially a short circuit, at that point there is no physical electrical contact provided between the tubular member and the plunger, thus overcoming several disadvantages of prior art resonators which utilized "finger" electrical contact at that point.