Micromachined waveguide antennas for 1.6 THz

J.W. Bowen, S. Hadjiloucas, B.M. Towlson, L.S. Karatzas,
S.T.G. Wootton, N.J. Cronin, S.R. Davies, C.E. McIntosh,
J.M. Chamberlain, R.E. Miles and R.D. Pollard

A new type of horn antenna for operation at 1.6 THz, that can befabricated monolithically with 1/4-height micromachined waveguide, is described. Height limitations imposed by the micromachining process are overcome by removing a tapered slot in the upper surface of a scalar horn, allowing the E-plane fields to extend outside the confines of the metallic structure before radiation, with a consequent reduction in E-plane beamwidth. 1.6 THz radiation pattern measurements for different designs show that, while there is scope for further optimisation, 3 dB beamwidths of 24° and 17.5° in the E- and H-planes, respectively, can be achieved.

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Diamagnetic Response of Metallic Photonic Crystals at Infrared and Visible Frequencies

Xinhua Hu,1 C. T. Chan,2 Jian Zi,3 Ming Li,1 and Kai-Ming Ho1

1Ames Laboratory and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
2Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
3Surface Physics Laboratory (National Key Lab), Fudan University, Shanghai 200433,

We show analytically and numerically that diamagnetic response (effective magnetic permeability miu_e <>

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