No abstract

No abstract

No abstract

The number of waveguides crossing an intersection increases with the development of complex photonic integrated circuits. Numerical simulations are presented to demonstrate that Maxwell's fish-eye (MFE) lens can be used as a multiband crossing medium. In previous designs of waveguide intersection, bends are needed before and after the intersection to adjust the crossing angle resulting in a larger footprint. The presented design incorporates the waveguide bends into the intersection which saves footprint. In this paper, 4×4 and 6×6 intersections based on ideal and graded photonic crystal (GPC) MFE lenses are investigated, where 4 and 6 waveguides intersect, respectively. The intersection based on ideal MFE lens partially covers the O, E, S, C, L, and U bands of optical communication, while the intersection based on GPC-MFE lens is optimized to cover the entire C-band. For 4×4 and 6×6 intersections based on GPC-MFE lens, crosstalk levels are below -24dB and -18dB, and the average insertion losses are 0.60dB and 0.85dB in the C-band with lenses' radii of 7×a and 10×a, respectively, where a is the lattice constant of the photonic crystal.

In this article, a novel square monopole antenna for ultra wideband applications with variable frequency band‐notch characteristic is presented. By using T‐shaped slots, additional resonances are excited and hence, the fractional bandwidth is increased up to 150%. A modified T‐shaped conductor‐backed plane is used to generate the frequency band‐stop performance. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 2065–2069, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25395