National University of Defense Technology

About: National University of Defense Technology is a education organization based out in Changsha, China. It is known for research contribution in the topics: Computer science & Radar. The organization has 39430 authors who have published 40181 publications receiving 358979 citations. The organization is also known as: Guófáng Kēxuéjìshù Dàxué & NUDT.

Miniaturized Frequency-Selective Rasorber With a Wide Transmission Band Using Circular Spiral Resonator

Abstract: This paper presents a miniaturized frequency-selective rasorber (FSR) that has a wide transmission band with low insertion loss and a wide absorption band below the transmission band. The FSR is composed of a resistive sheet and a bandpass frequency-selective surface (FSS). The unit cell of the resistive sheet is a resistor-loaded hexagonal metallic loop, each side of which is inserted with a circular spiral resonator (CSR) in the center. The CSR is equivalent to a parallel LC circuit that has a high inductance and low parasitic capacitance. At a high frequency of 10 GHz, the CSR resonates to be infinite impedance, around which a 0.5 dB transmission band of 8.68–11.34 GHz is produced. The bandpass FSS is a triple-layer FSS in which two layers of identical hexagonal patches are coupled through a layer of hexagonal aperture; it has a fast rolloff 0.5 dB transmission band of 8.2–11.33 GHz, which almost coincides with that of the resistive sheet. The 1 dB transmission band of the FSR by placing the resistive sheet on the bandpass FSS is 8.3–11.07 GHz. At low frequency, the FSR performs as an absorber, and the 10 dB absorption band is 2.4–7.1 GHz. In addition, due to its tiny physical sizes of only $1.2\,\,\text {mm}\times 1.6$ mm, the CSR can be viewed as a lumped element circuit with a high inductance, in which the parallel resonance is almost independent to the incident angle. The transmission performance of the FSR has a good independence of polarizations and incident angles. A prototype of the proposed FSR is fabricated and measured to validate the design.

A Miniaturized Absorptive Frequency Selective Surface

Abstract: A miniaturized absorptive frequency selective surface (MAFSS) is presented in this letter, composed of a layer of miniaturized resistive surface placed above a metallic bandpass FSS. The MAFSS performs as a bandpass filter at operation band around 0.92 GHz, and acts as an absorber over a wide out-of-band 3–9 GHz. Moreover, due to its miniaturized elements, the MAFSS exhibits the property of eliminating the grating lobe in absorption band when illuminated by oblique incident wave. Numerical and experimental results have been given.

Hybrid Spoof Surface Plasmon Polariton and Substrate Integrated Waveguide Transmission Line and Its Application in Filter

Abstract: In this paper, spoof surface plasmon polariton (SPP) is integrated in the closed substrate integrated waveguide (SIW) structure and a novel hybrid SIW-SPP guided-wave transmission line (TL) is proposed. In this design, the surface wave mode of SPP can be excited and transmitted inside the closed structure of SIW. The dispersion property of the proposed SIW-SPP hybrid structure indicates that it has both slow wave feature of SPP and fast-wave feature of SIW. With the low-pass feature of SSP and the high-pass feature of SIW, the proposed hybrid SIW-SPP TL becomes a bandpass filter (BPF) naturally. The concept of integrating SPP and SIW opens a new way to develop novel wideband BPFs. A broadband filter is fabricated to verify the theory and the measured passband is from 16.1 to 25.4 GHz with a relative bandwidth of 43.8%. The filter bandwidth can be easily controlled by tuning parameters, thus the proposed structure is attractive and useful for the design of various BPFs.