Multi-band feed assembly for linear and circular polarization

A back end, for an orthogonal mode transducer that includes a port for exchanging signals of a certain polarization, the back end comprising:

• (a) a diplexer, for being coupled operationally to said port;
• (b) a block up-converter;
• (c) a low noise block;
• (d) a receive reject filter wherethrough said block up-converter is operationally coupled to said diplexer;
• and
• (e) a transmit reject filter, wherethrough said low noise block is operationally coupled to said diplexer,
• wherein said diplexer is load matched to said filters in a band where the signals are being exchanged.

A waveguide comprising:

• (a) a distal section;
• (b) a medial section;
• and
• (c) a proximal section;
• wherein said distal section and said medial section are configured to rotate relative to each other and relative to said proximal section;
• wherein, when said distal section and said medial section are in a first configuration relative to each other and to said proximal section, the waveguide transforms linearly polarized electromagnetic radiation input to a proximal end of said proximal section into linearly polarized electromagnetic radiation output from a distal end of said distal section and transforms linearly polarized electromagnetic radiation input to said distal end of said distal section into linearly polarized electromagnetic radiation output from said proximal end of said proximal section;
• wherein, when said distal section and said medial section are in a second configuration relative to each other and to said proximal section, the waveguide transforms linearly polarized electromagnetic radiation input to said proximal end of said proximal section into circularly polarized electromagnetic radiation output from said distal end of said distal section and transforms circularly polarized electromagnetic radiation input to said distal end of said distal section into linearly polarized electromagnetic radiation output from said proximal end of said proximal section;
• wherein said distal section and said medial section are rotated differently with respect to each other in said second configuration than in said first configuration;
• and
• wherein
• said distal section and said medial section include respective eighth-wavelength polarizers, and
• said proximal section includes a quarter-wavelength polarizer.