JungAun Lee Jiro Hirokawa Makoto Ando Bandwidth Enhancement of Aperture Feed by an Air Rectangular Cavity Backing in a LTCC Post-Wall Waveguide. 121-126 2009 92-C IEICE Transactions 1 http://search.ieice.org/bin/summary.php?id=e92-c_1_121&category=C&year=2009&lang=E&abst= db/journals/ieicet/ieicet92c.html#LeeHA09