Mingbao Yan

Ultra-wideband polarization conversion metasurfaces based on multiple plasmon resonances

We propose to realize ultra-wideband polarization conversion metasurfaces in microwave regime through multiple plasmon resonances. An ultra-wideband polarization conversion metasurface is designed using a double-head arrow structure and is further demonstrated both numerically and experimentally. Four plasmon resonances are generated by electric and magnetic resonances, which lead to bandwidth expansion of cross-polarization reflection. The simulated results show that the maximum conversion efficiency is nearly 100% at the four plasmon resonance frequencies and a 1:4 3 dB bandwidth can be achieved for both normally incident x- and y-polarized waves. Experimental results agree well with simulation ones.

A Miniaturized Dual-Band FSS With Stable Resonance Frequencies of 2.4 GHz/5 GHz for WLAN Applications

In this letter, we propose an anchor-shaped loop unit-cell structure for compact frequency selective surfaces (FSSs) with dual-bandstop behavior in two wireless local area network (WLAN) frequencies 2.4 and 5.0 GHz. The proposed FSS possesses 230- and 300-MHz bandwidths with insertion loss less than -20 dB around the two central operating frequencies 2.4 and 5.0 GHz, respectively. In addition, the FSS exhibits excellent miniaturization with 0.065 λ × 0.076 λ unit cells, where λ represents the free-space wavelength. Furthermore, the unit-cell structure provides a stable performance for both TE- and TM- polarizations under incident angles 0°-60°. A prototype of the proposed FSS is fabricated and measured. Good agreement between the simulated and measured results is obtained.

A Novel Miniaturized Frequency Selective Surface With Stable Resonance

In this letter, a novel bandpass frequency selective surface (FSS) with miniaturized periodic element is presented. The proposed FSS is printed on one face of a single-layer substrate with a relative permittivity of 2.65. The novel FSS has promising miniaturization characteristics with the unit-cell dimension 0.058λ×0.058λ, where λ represents the free-space wavelength corresponding to the resonant frequency. The FSS exhibits excellent stability under different polarizations and incident angles. Both the simulation and measurement results validate the stable performance of this FSS.

A Miniaturized Dual-Band FSS With Second-Order Response and Large Band Separation

In this letter, a miniaturized dual-band frequency selective surfaces with second-order band-pass response at each operation band is presented. The design is implemented by cascading a two-dimensional periodic array of double square loops and an array of wire grids. The proposed structure composed of three metal and two dielectric layers acts as a spatial dual band microwave filter with large band separation. The predicted FSS has the merits of broadband response, excellent stability for different incident angles, and sharp roll-off at X- and Ka-band, respectively. The simulation and measurement are carried out and further discussed. A good agreement between simulated and measured results verifies the design of the dual-band FSS.

A Tri-Band, Highly Selective, Bandpass FSS Using Cascaded Multilayer Loop Arrays

A highly selective tri-band bandpass frequency-selective surface (FSS) is presented by cascading three layers of periodic arrays. The middle layer is composed of double square loops (DSLs) while the two exterior layers are composed of gridded-double square loops (G-DSLs) structure. The proposed FSS can provide multitransmission zeros which lead to a wide out-of-band rejection between each two adjacent passbands and sharp rejection behavior on both sides of each passband. Furthermore, the FSS exhibits stable response over a wide range of incident angles for both TE and TM polarizations. The design procedure, simulation, and experiment of the FSS are presented. The measured results are in good agreement with the simulations.

Achieving all-dielectric metamaterial band-pass frequency selective surface via high-permittivity ceramics

In this paper, we propose the design of all-dielectric metamaterial band-pass frequency selective surfaces (FSSs) using high-permittivity ceramics based on effective medium theory and dielectric resonator theory. The band-pass response can be determined by the permittivity of the dielectric material, the periodicity, and geometrical shape of the dielectric unit cell. As an example, a band-pass FSS composed of H shaped ceramic resonators is demonstrated. Both the simulation and experiment results show that the FSS can achieve a pass band in X-band. Since such FSSs are made of low-loss high-permittivity ceramics, they are of important application values, especially in high-temperature, high-power environments. The design method can be readily extended to the design of FSSs in other frequencies.

Ultra-Wide-Band Microwave Composite Absorbers Based on Phase Gradient Metasurfaces

In this paper, we propose to realize ultra-wide-band absorber (UWBA) based on anomalous refraction/reflection of phase gradient metasurfaces (PGM). To achieve high absorption and meanwhile keep small thickness at low frequencies, PGM is incorporated into conventional magnetic materials (MM). The absorptivity is increased due to prolonged propagation length in the MM, which is produced via anomalous refraction/reflection mediated by the PGM. Three typical composite configurations of PGM-based absorbers are investigated and an UWBA design method is finally formulated. Due to small thickness and ultra-wide bandwidth, such absorbers possess great application potentials in EM protection, RCS reduction, etc..

A Quad-Band Frequency Selective Surface With Highly Selective Characteristics

In this letter, a new quad-band frequency selective surface (FSS) is designed by cascading three metallic layers separated from one another by two thin dielectric substrates. Each exterior layer is a periodic array of gridded-triple square loops (G-TSLs) while the middle layer is an array of double square loops (DSLs). Two adjacent pass-bands are separated by two transmission zeros, which leads to a sharp rejection response on both sides of each band. Both the simulated and measured results validate the performance of the proposed FSS.

A novel miniaturized dual-stop-band FSS for Wi-Fi application

In this paper, we propose a new miniaturized dual band frequency selective surface (FSS) for Wi-Fi applications. The proposed FSS possesses 0.42 GHz and 0.30 GHz bandwidths with insertion loss less than -15 dB around the two central operating frequencies 2.4 GHz and 4.6 GHz, respectively. The FSS exhibits excellent miniaturization with 0.057λ₁ × 0.057λ₁ or 0.11λ₂×0.11λ₂ unit cells, where λ₁ and λ₂ represent the free-space wavelengths of two operating bands. Furthermore, the unit cell structure provides a stable performance for both TE and TM polarizations under incident angles up to ±60°. A prototype of the proposed FSS is fabricated and measured. The measured results agree well with the simulated results.

Hybrid metasurfaces for microwave reflection and infrared emission reduction

Controlling of electromagnetic wave radiation is of great importance in many fields. In this work, a hybrid metasurface (HMS) is designed to simultaneously reduce the microwave reflection and the infrared emission. The HMS is composed of the metal/dielectric/metal/dielectric/metal configuration. The reflection reduction at microwave frequencies mainly results from the phase cancellation technique, while the infrared emission reduction is due to the reflection of the metal with a high filling ration in the top layer. It has been analytically indicated that reflection reduction with an efficiency larger than 10 dB can be achieved in the frequency band of 8.2-18 GHz, and this has been well verified by the simulated and experimental results. Meanwhile, the designed HMS displays a low emission performance in the infrared band, with the emissivity less than 0.27 from 3 to 14 μm. It is believed that our proposal may find the application of multispectral stealth technology.