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This paper studies the electromagnetic properties of defected ground structure (DGS) with von Koch snowflake fractals. First, the snowflake fractal is employed in the dumbbell shaped DGS, and we have discovered that it has the characteristics of a low-pass filter and the out-of-band rejection increases with fractal iterations. In consideration of fabrication accuracy and performance, the third iteration has been adopted. Based on this structure, we have designed a narrow-band filter and a wide-band filter to verify our theory. From the simulated and measured results, we can see that the out-of-band rejection level has been greatly improved. The proposed structure can be applied in communication planar circuits.

At present, urban computing and intelligence has become an important topic in the research field of artificial intelligence. On the other hand, computer vision as a crucial bridge between urban world and artificial intelligence is playing a key role in urban computing and intelligence. Conventional particle filter is derived from Karman filter, which theoretically based on Monte Carlo method. Sequential importance resampling (SIR) is implemented in conventional particle filter to avoid the degeneracy problem. In order to overcome the shortcomings of the resampling algorithm in the traditional particle filter, we proposed an optimized particle filter using the maximum variance weight segmentation resampling algorithm in this paper, which improved the performance of particle filter. Compared with the traditional particle filter algorithm, the experimental results show that the proposed scheme outperforms in terms of computational consumption and the accuracy of particle tracking. The final experimental results proved that the quality of the maximum variance weight segmentation method increased the accuracy and stability in motion trajectory tracking tasks.

We theoretically and experimentally demonstrate a scheme to implement bipolar millimeter-wave (MMW) ultrawideband (UWB) monocycles using a nonlinear optical loop mirror (NOLM). A 20-GHz optical clock as the probe light and a Gaussian pulse as the pump light are launched into the NOLM for cross-phase modulation (XPM). At the reflection and transmission ports of the NOLM, a pair of polarity-reversed MMW-Gaussian pulses is generated due to constructive and destructive interferences. They are then mixed with proper time delay and orthogonal polarization states. Thus, a photonic MMW-UWB monocycle is obtained. By adjusting the time delay between the reflection and transmission ports of the NOLM, bipolar MMW-UWB pulses are generated.

We experimentally demonstrate an arbitrary-order bandwidth-tunable differentiator using a programmable optical pulse shaper, which is based on spatial diffraction and liquid crystal modulation. The impact of bandwidth of optical pulse shaper on output power and pulsewidth of differentiation is theoretically analyzed. In the experiment, all first-order, second-order, and third-order differentiators with bandwidths of 80, 160, and 320 GHz are obtained with average deviations of less than 4.2%. The differentiation of pseudorandom nonreturn-to-zero (NRZ) signals at 10 and 20 Gbit/s is also discussed.