WAVEGUIDE APPARATUS AND METHOD FOR DUAL POLARIZED AND DUAL FREQUENCY SIGNALS

摘要

WAVEGUIDE APPARATUS AND METHOD FOR DUAL POLARIZED AND DUAL FREQUENCY SIGNALS A waveguide apparatus guides a first pair of horizontally polarized transmit and receive frequency signals independently of and in parallel with a second pair of vertically polarized transmit and receive frequency signals. The waveguide apparatus guides the two pairs of orthogonally polarized frequency signals between a feed horn and related transmitter and receiver units at the antenna of an earth station. The waveguide apparatus includes a polarization junction for separating the pairs of frequencies by polarization and two frequency separators for separating the transmit from the receive signal in each polarized pair. Each of the frequency separators has a planar filter with interspersed bandpass and band-stop structure located in one port and susceptance blocks located in another port for maintaining isolation between the transmitter and receiver units. The polarization junction is orthogonally coupled to the horizontal frequency separator by a coupling having symmetrical H-plane bends, E-plane bends and a Southworth junction which are effective in combination with septums in the polarization junction to produce inherent broadband operation without tuning. The four port configuration with dual orthogonal polarizations and broadband operation permits dual path redundancy for communications users with only one antenna. The waveguide apparatus is physically short and structurally robust, and all of the ports terminate at a common plane so that the waveguide apparatus can be and is used as a structural member for supporting all of the electronics within the antenna mount, and directly at the outlet of the waveguide apparatus. The structure and operation of the wave guide apparatus enable each of the transmitter and receiver units to be a replaceable unit which can be removed or replaced without interfering with the transmission or reception of any of the other three signals.