Dual frequency antenna feed with apertured channel

A coupling arrangement for coupling microwave signals between a coaxial waveguide section and a horn antenna, wherein the coaxial waveguide section includes a common region between inner and outer conductors for propagating a first signal in a first frequency band and the inner conductor acts as a circular waveguide for propagating at least a second signal in a second frequency band, the coupling arrangement comprising:

• a conically shaped section defined at least in part by a narrow aperture-defining perimeter and a wide aperture-defining perimeter with a channel therethrough, and a side wall, between the wide and narrow aperture-defining perimeters, with a plurality of irises therethrough, wherein the wide aperture-defining perimeter is coupled to the outer conductor of the coaxial waveguide section and to the horn antenna and the narrow aperture-defining perimeter is coupled to the inner conductor of the coaxial waveguide section;
• a dielectric rod situated through the conically shaped section and into the horn antenna for propagating the second signal between the inner conductor of the coaxial waveguide section and an atmosphere adjacent the horn antenna;
• wherein the propagation path for the first signal is defined by the common region of the coaxial waveguide section, the irises, the channel and the wide aperture-defining perimeter of the conically shaped section and the horn antenna, and the propagation path for the second signal is defined by the inner conductor of the coaxial waveguide section, and the dielectric rod through the channel of the conically shaped section and into the horn antenna.

A waveguide coupling arrangement for propagating a first signal in a first frequency band and at least one second signal in a second frequency band, comprising:

• a waveguide section including propagation means for propagating the first signal in a TE.sub.11 coaxial mode in a common region therein and for propagating the second signal in a TE.sub.11 circular waveguide mode in another region therein;
• a microwave element for providing HE.sub.11 waveguide mode operation for the first and second signals;
• and
• junction means, coupled to and disposed between the microwave element and the waveguide section, including elongated channel means for providing a substantially continuous transformation between the TE.sub.11 circular and HE.sub.11 waveguide modes for the second signal and wherein the elongated channel means has a side wall with a plurality of irises therethrough for providing a propagation path for the first signal between the common region and the microwave element and for transforming the first signal between the TE.sub.11 coaxial and HE.sub.11 waveguide modes.

A waveguide coupling arrangement for propagating a first signal in a first frequency band and at least one second signal in a second frequency band, comprising:

• a waveguide section including propagation means for propagating the first signal in a common region therein the TE.sub.11 coaxial mode and for propagating the second signal in the TE.sub.11 circular waveguide mode in another region therein;
• a microwave element for providing TE.sub.11 circular waveguide mode operation for the first and second signal;
• and
• junction means, coupled to and disposed between the microwave element and the waveguide section, including a conically shaped section having a side wall with a plurality of irises therethrough for providing a propagation path for the first signal between the common region and the microwave element and for providing a transformation between the TE.sub.11 coaxial and TE.sub.11 circular waveguide modes for the first signal.

A dual band feed system for a microwave antenna comprising:

• a coaxial waveguide section having an inner and an outer conductor and including
• a first port for providing a propagation path for a first signal in a first frequency band,
• a second port for providing a propagation path for second and third signals in a second frequency band,
• wherein the first signal propagates in a common region between the outer and inner conductors in a TE.sub.11 coaxial mode and the second and third signals each propagate in the inner conductor in a TE.sub.11 circular waveguide mode;
• a combining junction comprising:
• a conically shaped section having a narrow aperture-defining perimeter and a wide aperture-defining perimeter and with a channel therethrough, and a side wall, at least partly defining the conical shape, with a plurality of irises therethrough to provide a path for the first signal from the common region to the microwave antenna and to provide a transformation between the TE.sub.11 coaxial mode and HE.sub.11 waveguide mode for the first signal, wherein the conical shape provides a continual transformation of the TE.sub.11 circular waveguide mode to HE.sub.11 waveguide mode for the second signal,
• a ring section, coupled between the inner conductor of the coaxial waveguide section and the narrow aperture-defining perimeter of the conically shaped section, through which the second signal propagates;
• wherein the wide aperture-defining perimeter is coupled to the outer conductor of the coaxial waveguide section and to the antenna;
• and
• a dielectric rod extending from within the inner conductor, through the ring and the conically shaped sections of the combining junction and into the horn antenna for propagating the second signal.