In this paper, a novel slow-wave half mode substrate integrated waveguide (SW-HMSIW) structure is presented and experimentally demonstrated, and some interesting slow-wave propagation effects are obtained. The SW-HMSIW enables the cutoff frequency reduction and phase velocity to decrease without sacrificing its performance at the same lateral dimension, which equivalently reduces the lateral dimension and longitudinal size at the same frequency. Specifically, with the different loading microstrip width, a cutoff frequency reduction of 16%, 25%, 30% is achieved compared to the conventional HMSIW at the same lateral dimension. Both lateral and longitudinal size reductions significantly extend the operating range of SIW structures to low frequency region.

Point cloud video contains not only color information but also spatial position information and usually has large volume of data. Typical rate distortion optimization algorithms based on Human Visual System only consider the color information, which limit the coding performance. In this paper, a Coding Tree Unit (CTU) level quantization parameter (QP) adjustment algorithm based on JND and spatial complexity is proposed to improve the subjective and objective quality of Video-Based Point Cloud Compression (V-PCC). Firstly, it is found that the JND model is degraded at CTU level for attribute video due to the pixel filling strategy of V-PCC, and an improved JND model is designed using the occupancy map. Secondly, a spatial complexity detection metric is designed to measure the visual importance of each CTU. Finally, a CTU-level QP adjustment scheme based on both JND levels and visual importance is proposed for geometry and attribute video. The experimental results show that, compared with the latest V-PCC (TMC2-18.0) anchors, the BD-rate is reduced by -2.8% and -3.2% for D1 and D2 metrics, respectively, and the subjective quality is improved significantly.