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Abstract-The stability and dispersion performance of the recently developed Battle-Lemarie multiresolution time-domain schemes is investigated for different stencil sizes. The contribution of wavelets is enhanced and analytical expressions for the maximum allowable time step are derived. It is observed that larger stencils decrease the numerical phase error, making it significantly lower than finite-difference time domain for low and medium discretizations. The addition of wavelets further improves the dispersion performance for discretizations close to the Nyquist limit, though it decreases the value of the maximum time step, guaranteeing the stability of the scheme.

Abstract-An active interference cancellation scheme is presented to mitigate interference between Bluetooth and wireless local area network (IEEE 802.11 b) radios operating in close proximity. This method is extensible to other mutually interfering radio devices. A reference signal correlated to the original interferer is used to generate a cancellation signal by means of amplitude and phase alignment, and filtration. The filter employed emulates the coupling channel responsible for interference. An implementation of this procedure in 0.18-m Si-complementary metal-oxide-semiconductor (CMOS) integrated-circuit (IC) technology is also presented. The circuits fabricated are tunable and are controlled by a closed-loop adaptive process including an error minimization method. The cancellation system designed achieves 15-30 dB of interference suppression for different cases. A total power of 14 mW is dissipated by the CMOS ICs designed.

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Abstract-A space-and time-adaptive two-dimensional multiresolution time-domain (MRTD) algorithm based on arbitrary resolutions of Battle-Lemarie wavelets is proposed. Analytic expressions for the finite-summation coefficients are derived and details concerning the modeling of hard boundaries, excitation, and field reconstruction are extensively discussed. Through the use of a combination of absolute and relative thresholding, a dynamically changing grid is developed with minimal computational requirements in comparison to the finite-difference time-domain technique. After the validation process, MRTD is used for the first time for the numerical optimization of complex RF structures such as evanescent-mode filters.