Huangyan Li

A Novel 2-B Multifunctional Active Frequency Selective Surface for LTE-2.1 GHz

This paper proposes a 2-b multifunctional active frequency selective surface (MAFSS) whose structure is made up of two metallic layers printed on both sides of an F4BME substrate, measuring

Reconfigurable electromagnetic shield by AFSS for 4G mobile communications

320 \times 320 \times 0.8

A DUAL-POLARIZED SWITCHABLE ACTIVE FREQUENCY SELECTIVE SURFACE FOR LTE-D BAND

mm3. The PIN diodes, embedded on two metallic layers, are controlled through two independent sets of external dc bias network. No additional feeder lines are considered necessary within the MAFSS array, which weakens the bias network’s negative impact on the transmission characteristics of the MAFSS. Using an innovative and effective diode switching technique, two functions (electromagnetic switch and polarization selection) and thus four working states (dual-polarized bandpass for code “00,” dual-polarized shielding for code “11,” TE wave selection for code “10,” and TM wave selection for code “01”) have been realized. The equivalent circuit method and the surface current analysis have been used for a better understanding of the physical principles of the design. A prototype of the proposed structure has been fabricated and measured. The measurements have shown a good agreement between the simulated and the measured results, demonstrating thereby that the proposed structure can give excellent performance. Using the results of extensive numerical and experimental studies, the proposed structure has also been proved to give stable performance, with respect to different incident angles and wave polarizations around LTE-2.1 GHz.

Study of miniaturized tri-band combined-element frequency selective surface (CEFSS)

A reconfigurable electromagnetic shield by active frequency selective surface (AFSS) with switch function at LTE-D 4G mobile communication is proposed in this paper. Double coupled metallic meandered structures on one layer substrate loaded PIN diodes are designed carefully to realize the band-pass characteristic at 2.6GHz when PINs are OFF and the rejection characteristic when PINs are ON. The proposed model required no additional biasing lines and the amount of PINs is affordable, which contribute to the practicality in real applications. The polarization-insensitivity and angle-stability are analyzed through the simulation results.

Reconfigurable shield by active frequency selective surface for LTE2.1GHz and WiFi2.45GHz

A dual-polarized active frequency selective surface (AFSS) with switch function at LTE-D band is proposed in this paper. Double coupled metallic meandered structures on a one-layer substrate loaded PIN diodes are designed carefully to realize the band-pass characteristic at 2.6 GHz when PINs are OFF and the rejection characteristic when PINs are ON. The proposed model requires no additional biasing lines, and the amount of PINs is acceptable and affordable, which contribute to the simplicity and practicality of this AFSS in real applications. A simple equivalent circuit model (ECM) is given to better understand the design. Through full-wave simulation results, the polarization characteristics under TE and TM are almost the same, and the angle-stability stays well till 45◦. For necessary verification, one finite FSS prototype was fabricated, which was changed to one switchable AFSS by welding PINs and external feeder lines. The measured results of transmission coefficient are obtained by free space test method in the microwave anechoic chamber and agree well with the simulated ones.

A novel active frequency selective surface with switching performance for 2.45 GHz WLAN band

Miniaturized combined-element frequency selective surfaces (CEFSSs) for tri-band applications are proposed using complementary structures. The three pass-bands of the proposed structures can be designed independently, which makes the design process much easier and more flexible than traditional tri-band FSSs. Besides, comparing to former designed combined-element FSSs, the structures proposed in this paper have smaller sizes due to the use of meandered structures, which contributes to its independence of both angle and polarization. Equivalent circuit method (ECM) is used to analyze transmission characteristics. The results between simulation and measurement agree well.

An Ultrathin Bandpass Frequency Selective Surface With Miniaturized Element

Two novel active frequency selective surfaces (AFSS) are proposed in this paper. Long Term Evolution (LTE)-AFSS and WiFi-AFSS are made up of square loop patch and half circular loop patch for shielding 2.1GHz and 2.45GHz signals respectively. PIN diodes inside AFSSs are used to realize the switching between transmission and reflection characteristics. In addition, both AFSSs have large holes for the purpose of ventilation and heat dissipation. Equivalent circuit model (ECM) and resonance theory analysis are provided to validate the simulation. The detailed results of different incident wave angles(0°/30°/60°) are also given in this paper.