Non-reciprocal mode converting substrate integrated waveguide

A circulator, comprising:

• a non-reciprocal mode converting substrate integrated waveguide (SIW) configured to:
• (i) in a forward propagating direction:
• excite waves in a first TE mode in a first straight section of the SIW to propagate towards a curved section of the SIW;
• and bend the waves propagating in the curved section to convert the waves to a second TE mode in a second straight section of the SIW;
• (ii) in a reverse propagating direction:
• excite waves in the first TE mode in the second straight section to propagate towards the curved section;
• and bend and magnetically bias the waves propagating in the curved section to maintain the waves in the first TE mode in the first straight section;
• and
• a second SIW coupled to the second straight section and configured to extract waves in the second TE mode from the second straight section.

A method of non-reciprocal mode conversion using a SIW, comprising:

• in a forward propagating direction:
• exciting TE10 mode waves in a first straight section of the SIW to propagate towards a curved section of the SIW;
• and
• bending the TE10 mode waves propagating in the curved section to convert the TE10 mode waves to TE20 mode waves in a second straight section of the SIW;
• and
• in a reverse propagating direction:
• exciting TE10 mode waves in the second straight section to propagate towards the curved section;
• and
• bending and magnetically biasing the TE10 mode waves propagating in the curved section to maintain the TE10 mode waves as TE10 mode waves in the first straight section.