As silicon radars have become commonplace at microwave and millimeter-wave frequencies driven by automotive and other sensing applications, two specific architectures for these radars have become dominant in the literature: frequency-multiplied radar systems and upconverted radar systems. While both architectures are well reported, the literature in microwave theory and technology thus far does not offer a robust quantitative comparison of the two approaches regarding their radar behavior, especially in the case of dynamic range.

This paper presents a method for designing transmit beampattern in Four Dimensional (4D) imaging automotive Multiple-Input Multiple-Output (MIMO) radars, employing the distance between the designed and desired beampatterns as the design metric. The paper demonstrates that the proposed method outperforms the commonly used omnidirectional beampattern across various automotive scenarios, highlighting its superior adaptability and utility in multiple applications. 

An important challenge in group target tracking is the separation of individual targets within the group. Group target separation can lead to significant fluctuations in the position of the group center and the shape of the group, leading to decreased tracking accuracy and potential target loss. Moreover, when the target group consists of multiple objects with uncertain spatial positions, especially during separation, rapidly reconstructing the shape of the group target becomes challenging. This paper proposes a novel method for detecting separation events and stable tracking to address related issues. 

A novel method of designing broadband wide-angle frequency selective surface (FSS) is proposed. First, based on effective media theory, perfect transparency can be realized for FSS when the equivalent permittivity equals permeability, which provides transmission poles. Second, the effective permeability and permittivity can be regulated by electrical resonance and magnetic resonance. Third, a new transmission pole is introduced to extend the passband width by loading square rings onto the upper and lower layers. 

This paper introduces a dual band-pass and dual band-stop filter that is designed along its flexible back-end circuitry to sense and monitor muscle contractions. The filter and its back-end circuit are proposed to be wearable, flexible, and stretchable. The presented design is composed of several logarithmically scaled spiral-shaped defected ground structures (DGS) located along the ground plane of a co-planar waveguide transmission line. In addition, U-shaped slots are integrated within the transmission line to maintain the sensing operation of the filter when its structure is stretched.