arXiv subjects

Binchao Zhang

Publications and source records attributed to Binchao Zhang.

6 recordsLinked to original sources

arXiv2025

Design of A Single Antenna With Tunable In-Band RCS Null Through Load Impedance Control

Reducing the in-band radar cross section (RCS) of antennas has been a widely concerned problem. However, most of works focus on RCS reduction of antenna arrays, or need to additionally increase the size of a single antenna. Therefore, this work presents a method to control the null of the in-band RCS by changing the load impedance of the antenna without additional aperture. Then, the monostatic and bistatic RCS can be effectively reduced. First, the relationship between the null position and the load impedance is calculated by analyzing the in-band scattering field of the antenna. Second, the performance of RCS null control is verified by the traditional patch antenna, whose operating frequency is designed at 2 GHz. The load impedance of the antenna is controlled by cascading an open circuit stub of different lengths on the feeding line. Simulated results show that the proposed method can tune the null of in-band RCS from 0o to 60o under linear polarized normally incident plane wave. By setting the null reasonably, it can achieve 10 dB reduction for both monostatic and bistatic RCS at the same time. Moreover, the radiation performance of the antenna basically remains unchanged, and the gain is greater than 6.5 dBi. Measured results verify the effectiveness of the design method.

physics.app-ph↗

arXiv2024

X-RIS: A Study of the Principles and Applications of X-Shaped RIS

This paper analyzes the working principle of X-Shaped reconfigurable intelligent surface (RIS) in detail and reveals the different types of RIS that can be designed based on this structure. Combined with the design examples using this structure in the currently published articles, this paper summarizes and organizes them, and finally, based on this X-Shaped structure, this paper explores some other possible designs, which reflects the potential of the design versatility of the X-RIS structure.

cs.CE↗

arXiv2024

A Study of Four-Switch Cross-Shaped RIS and A Novel Design Example

This paper analyzes the working principle of four-switch cross-shaped reconfigurable intelligent surface (RIS) in detail and reveals the different types of RIS that can be designed based on this structure. Combined with the design examples using this structure in the currently published articles, this paper summarizes and organizes them, and also points out several RIS solutions that have not been designed using this structure. Finally, based on this four-switch cross-shaped structure, this paper proposes a novel RIS design example that can realize the function switching of 1-bit ultra-wideband (UWB) and 2-bit narrowband, and conducts simulation verification. The simulation results show that by optimizing the element structure and controlling the states of the four switches, the 1-bit ultra-wideband function can achieve a frequency band coverage of 10.5GHz-19.8GHz and a 2-bit phase quantization function around 18.12GHz. At the same time, it can realize 60° two-dimensional beam scanning function. We call this novel design "bit reconfigurable metasurface".

physics.app-ph↗

arXiv2023

In-Band Co-Polarization Scattering Beam Scanning of Antenna Array Based on 1-Bit Reconfigurable Load Impedance

Controlling the in-band co-polarization scattering of the antenna while maintaining its radiation performance is crucial for the low observable platform. Thus, this paper studies the in-band co-polarization scattering beam scanning of antenna arrays. Firstly, the regulation method of antenna scattering is analyzed theoretically, concluding that the amplitude and phase of the antenna's scattering field can be regulated by changing the load impedance. Subsequently, PIN diodes are implemented to control the load impedance of the antenna. Consequently, the scattering of the antenna, ensuring that the antenna's scattering meets the condition of equal amplitude and a phase difference of 180° when the PIN diode switches, thereby realizing scattering beam scanning. Moreover, by introducing an additional pre-phase, the inherent symmetric dual-beam issue observed in traditional 1-bit reconfigurable structures is overcome, achieving single-beam scanning of the scattering. Finally, a 1{\times}16 linear antenna array is designed and fabricated, which operates at 6 GHz with radiation gain of 16.3 dBi. The scattering beams of the designed array can point to arbitrary angles within 45°, significantly reducing the in-band co-polarization backward radar cross section. The measured results align well with the simulated ones.

physics.app-ph↗

arXiv2023

1 Bit Electronically Reconfigurable Transmitarray Antenna with Out-of-Band Scatter Suppression

Stealthy electronically reconfigurable transmitarray antennas are essential components in wireless communication and radar detection systems. Therefore, this paper proposes a 1 bit electronically reconfigurable transmitarray antenna with out-of-band scatter suppression. The transmitarray consists of two layers, the absorptive frequency selective transmission (AFST) layer and reconfigurable transmitarray (RTA) layer, separated by air. Specifically, the AFST layer achieves out-of-band scattering suppression and in-band transmission performance by utilizing the first three resonant modes of a bent metallic strip with a centrally loaded resistor. Additionally, the RTA layer adopts a receiver-transmitter structure with an active receiving dipole and a passive orthogonal transmitting dipole. The 1 bit phase shift is achieved by alternating two pin diodes integrated on the active dipole to reverse its current direction. To evaluate the proposed design, a 256-element transmitarray prototype is designed, fabricated and measured. For scattering, the 10-dB radar cross section reduction is realized within 4~5.2 GHz and 10.9~11.4 GHz, respectively. For radiation, the measured gain is 19.9 dBi at 7.5 GHz, corresponding to an aperture efficiency of 12.1%. and the beam scanning covers 60° with gain loss of 5 dB in both two principal planes.

physics.app-ph↗

arXiv2022

Growth of a renormalized operator as a probe of chaos

We propose that the size of an operator evolved under holographic renormalization group flow shall grow linearly with the scale and interpret this behavior as a manifestation of the saturation of the chaos bound. To test this conjecture, we study the operator growth in two different toy models. The first is a MERA-like tensor network built from a random unitary circuit with the operator size defined using the integrated out-of-time-ordered correlator (OTOC). The second model is an error-correcting code of perfect tensors, and the operator size is computed using the number of single-site physical operators that realize the logical operator. In both cases, we observe linear growth.

hep-th↗