Dual-band coaxial feed system with ridged and T-septum sectoral waveguides

A new OMJ using a junction of quad T-septum coaxial waveguide and four T-septum sectoral waveguides is proposed for excitation of the lower band in a dual-band feed system. The proposed structure is analysed using FEM. The result is compared with the previously proposed ridged OMJ structure. Further, the paper investigates the methods to diplex the dual-band CP waves from the similar ridged OMJ structure and newly proposed T-septum structure. An integrated coaxial OMJ/OMT is proposed to replace all individual components in the circuit for exciting CP waves in the lower band. The new CP wave exciting structure is compact and easy for manufacture. It offers an alternative design for the applications that require compact structure.