Narrow Results

One-dimensional defective binary photonic crystal is considered with the structure (AB)${}^N$D(AB)${}^N$, where A (TiO${}_2)$ and B (SiO${}_2)$ are the layers constituting the photonic crystal and D is the defect layer. The temperature dependence of the defect mode is investigated by considering both thermo-optic and thermal expansion effects. As the refractive indices and thicknesses of the photonic crystal layers are varied by temperature, the properties of the photonic crystal, such as bandgap and defect mode, are modified. Thus, we propose a tunable transmission filter operating in the visible region of the spectrum. It is found that the transmittance peak shift of the defect mode can be enhanced with the increase of both thermo-optic and the thermal expansion coefficients of the defect mode. As an example, we consider a photonic crystal with the structure (TiO₂–SiO${}_2{)}^6$/SiOC/(TiO₂–SiO${}_2{)}^6$ and a transmittance peak shift of the defect mode of 1.51 nm is obtained for a temperature increase of $100^{\circ }$C.

In this paper, a new realization of a current-mode first-order all-pass filter (APF) using a single active building block (ABB) and one grounded capacitor is presented. As the ABB, the current backward transconductance amplifier (CBTA) is used, which is one of the most recently reported active elements in the literature. The theoretical results are in detail verified by numerous SPICE simulations using a new low-voltage implementation of CBTA. In the design, the PTM 90nm level-7 CMOS process BSIM3v3 parameters with $\pm$0.45V supply voltages were used. The proposed resistorless CBTA-C APF provides easy electronic tuning of the pole frequency in the frequency range from 763kHz to 17.6MHz, which is more than one decade. Maximum power dissipation of the circuit is 828$\mu$W at bias current 233$\mu$A. Nonideal, parasitic effects, sensitivity analyses, temperature and noise variation, current swing capability, and Monte Carlo analysis results are also provided. Compared to prior state-of-the-art works, the proposed CBTA-C APF has achieved the highest figure of Merit value, which proves its superior performance.