The B16 Test beamline at the Diamond Light Source is in user operation. It has been recently upgraded with the addition
of a double multilayer monochromator (DMM), which provides further functionality and versatility to the beamline. The
multilayer monochromator is equipped with two pairs of multilayer optics (Ni/B4C and Ru/B4C) to cover the wide
photon energy range of 2 - 20 keV, with good efficiency. The DMM provides a broad bandpass / high flux operational
mode for the beamline and, when used in tandem with the Si (111) double crystal monochromator, it gives a very high
higher-order harmonics suppression. The design details of the DMM and the first commissioning results obtained using
the DMM are presented.
The variation of magnetic permeability of substrate on Photonic Band Gap (PBG) has been studied for microstrip type periodic metallic structure and the experimental findings will be presented and discussed. Periodic structure was carved out in the metallic foil of 18 micron thickness and was put on the composite of magnetic and dielectric substrate. As the dielectric constant of the substrate affects the band gap for the photons in the microwave region, the combined effect of magneto-dielectric substrate have been studied here for different combination of ferrite materials with different composition and different sintering temperature. The substrate of Ni-Zn ferrite was prepared on the Perspex sheet of desired dimensions. The behavior of variation of band gap was also been studied for the air as dielectric material of the substrate. We found a well defined PBG and the band gap increases and transmission loss decreases in the microwave region with appropriate combination of magnetic and dielectric substrate. Thus it could be concluded that the dielectric constant viz. a viz. magnetic permeability plays an important role in the formation of broad band photonic materials for the microwave applications such as filters, antennas, frequency selective surfaces etc. Further work is going on to fabricate the patch antenna on the PBG embedded ground plane.