Abstract: A dual mode antenna that allows both millimeter wave and infrared radiation o enter a single aperture and propagate through a common transmission device to a point where the respective energies are divided to follow separate paths for subsequent processing. An electromagnetic transmission guide or waveguide for the system comprises a tubular waveguide member, having a beam directing lens or lenses therein, for maintianing low-loss, gaussian beam propagation of millimeter wave energy therethrough. A waveguide fiber array is coupled into or adjacent to the tubular member at one end and retrieves the infrared radiation but allows the millimeter wave radiatin to pass. Cassegrainian optics are positioned adjacent the other end of the tubular member for directing incoming millimeter and infrared energy into the guide. Subsequently, the energy impinges on the beam directing lens means that separates the respective energies, dividing them into two separate and distinct paths.

Abstract: A dual mode antenna that allows both millimeter wave radiated energy and rared radiated energy to enter a single aperture and propagate through a common transmission device to a point where the respective energies are divided to follow separate paths for subsequent processing. An electromagnetic transmission guide for waveguide comprises first and second parallel tubular members having beam directing reflectors and lenses therein for maintaining low-loss, gaussian beam propagation of radiated energy therethrough. Cassegrainian optics of a cassegrainian antenna system are positioned for directing the millimeter and infrared energy into a common, circular end of said tubes where the energy impinges on beam directing means that separates the respective energies, directing them into the respective parallel tubes along two separate and distinct paths.