Abstract: A mobile-radio base station for a teleconununicaions system includes vector modulator means for independently controlling the phase and/or amplitude of a plurality of component signals representative of the signal to be transmitted or received, such that when these signals pass through a plurality of antenna elements, a beam is formed in a direction according to the phase relationship of the component signals. The base station further includes interface means allowing other base stations to be coupled to the same antenna, with each base station having independent control of its beam direction.

Abstract: A phased array antenna system with variable electrical tilt comprises an array (60) of antenna elements (60L1) etc. incorporating a divider (44) dividing a radio frequency (RF) carrier signal into two signals between which a phase shifter (46) introduces a variable phase shift. A phase to power converter (50) converts the phase shifted signals into signals with powers dependent on the phase shift. Power splitters (52, 54) divide the converted signals into two sets of divided signals with total number equal to the number of antenna elements in the array. Power to phase converters (561) etc. combine pairs of divided signals from different power splitters (52, 54) this provides vector sum and difference components with appropriate phase for supply to respective pairs of antenna elements (60U1, 60L1) etc. located equidistant from an array centre. Adjustment of the phase shift provided by phase shifter (46) changes the angle of electrical tilt of the antenna array (60).

Abstract: An antenna system for sharing of operation employs contiguous transmit frequencies. Transmit frequencies are separated into non-contiguous sub-groups isolated from one another by filters 158(+) and 160(?) associated with positive and negative polarisation. Received frequencies are filtered and split into five signals for input to base station receive ports. Non-contiguous transmit frequency sub-groups are combined by a quadrature hybrid 110 and pass with 90 degree relative phase shift to mutually orthogonal antenna stack ports P(+) and P(?) associated with orthogonally polarised sets of antenna elements AS(+) and AS(?): the ports P(+) and P(?) are isolated from one another by the hybrid 110. The 90 degree phase shift results in one transmit subgroup being radiated with left hand circular polarisation and the other transmit subgroup being radiated with right hand circular polarisation.

Abstract: An antenna system for use in transmitting and/or receiving at least two signals, whereby a first one of said signals is generated in a first operator frequency band by a first operator and a second one of said signals is generated in a second operator frequency band by a second operator wherein the antenna system comprises an antenna assembly having an adjustable angle of electrical tilt, and including a plurality of antenna elements (E1–En) for transmitting and/or receiving said signals, wherein the antenna elements are mounted upon an antenna carrier and are arranged in at least two sub-arrays, each sub-array including one or more of said elements, a control means for controlling electrically the phase of signals transmitted and/or received by said antenna assembly, thereby to control the angle of electrical tilt of said antenna assembly and a combiner means for enabling said antenna assembly to transmit and/or receive substantially simultaneously a first one of said signals at a first angle of electrical t

Abstract: An antenna system comprises an antenna assembly having an angle of electrical tilt and a plurality of antenna elements each arranged to receive signals through a respective transmission line. Each transmission line is shortened or lengthened by moving a coupling link along two transmission line parts which the link couples: this adjusts signal phase supplied to each antenna element individually, and controls the angle of electrical tilt of the antenna assembly.

Abstract: A transmit network for cellular mobile radio networks incorporates tow transmit multiplexers (122ABE) and (122CD): the first transmit multiplexer 122ABE receives a group of output signals from three transmitters (124A, 124B and 124E), and filters them in respective band-pass filters (126A, 126B and 126E); the second transmit multiplexer (122CD) receives a group of output signals from two further transmitters (124C and 124D), and filters them in respective band-pass filters (126C and 126D). The transmit frequencies in each signal group are non-adjacent, which improves isolation between transmitters provided by the filters (126). Filtered output signals from respective band-pass filters (126) are combined at filter outputs (128X and 128Y) from which signals are combined in a combiner (132) providing a degree of isolation between these outputs and enabling the signals to be combined with minimal distortion. Signals from the combiner (132) are fed via a duplexer to a transmit/receive antenna.