Abstract: A broadband antenna of miniature size employs an array of dipole elements whose inner ends are connected to a pair of closely spaced parallel central conductors. Three pairs of dipole elements are disposed in a symmetrical array and extend outwardly from the central conductors. The longest pair of dipole elements are capacitively end loaded and the length of that longest pair is approximately one eighth of a wavelength at the lowest frequency in the broadband. The length of the shortest pair of dipole elements is in the range of a third to a quarter of the wavelength at the highest frequency in the broadband. The third pair of dipole elements is a half wavelength at an intermediate frequency in the broadband. At the points where their inner ends are connected to the central conductors, adjacent pairs of dipole elements are spaced apart by a distance in the range of a half to a quarter of the wavelength at the highest frequency in the broadband.

Abstract: A four port magic tee device has three ports defined by an H arm and two parallel side arms which meet at a common junction of the device, and has a fourth (E) port at the junction. Extending over the fourth port is a section of waveguide which acts as a coupling and matching structure by providing a chamber which is coupled to that port. That arrangement enables the E arm of the magic tee device to be reduced to zero length, if desired. In contrast, the E arm of a conventional magic tee of comparable performance must be of some finite length.

Abstract: Under non-fault conditions the power from two equal power transmitters A and B having a relative phasing of 90.degree. is combined in the network of this invention to provide at an output thereof a power of A + B. The network preferably comprises two 3db short-slot 90.degree. couplers connected in cascade with the first coupler normally operating and the second coupler shorted or decoupled in the coupling slot region by means of shorting posts or the like. If transmitter B fails this condition is sensed and the second coupler has its associated decoupling means withdrawn so that the couplers form a zero db cross-over coupler delivering the total power of transmitter A to the output. For a failure condition of transmitter A a decoupling means is also associated with the first coupler so the entire network can be decoupled delivering the total power of transmitter B to the output under that condition. With a failure of either transmitter A or B there is the possibility of inoperation of the decoupling means.

Abstract: A compact device for launching circularly polarized electromagnetic waves utilizes a hollow waveguide terminated by a horn. Within that structure, a septum fin extends from the waveguide into the horn. The septum fin divides the hollow waveguide into two smaller waveguides, each of which is capable of independently supporting the TE.sub.1,0 mode of wave propagation. The fin is a tapered plate that has its maximum width within the waveguide and its minimum width in the horn. A signal injected into one port of the divided waveguide emerges from the horn as a circularly polarized wave having its polarization vector rotating clockwise whereas a signal injected into the other port emerges from the horn as a circularly polarized wave with its polarization vector rotating in the counter clockwise direction.