Xianbo Cao

The development of reconfigurable intelligent surfaces (RISs) is important to facilitate advances in beyond 5G and 6G technologies. However, the difficulty of controlling the reflected amplitude of the widely studied 1-bit reflectarray (RA) makes it difficult to meet the requirements of RIS for multiple application scenarios, and the change of the operating frequency in emerging time modulation (TM) technology-based RAs makes them unsuited to existing systems. Considering the observed the intrin

A dual-band absorber using monolayer periodically T-shaped slot-patterned graphene at terahertz frequencies is presented. By changing the dimensions or Fermi levels of the T-shaped slot-patterned graphene, both of the two absorption bands will be adjusted. The absorber has the characteristics of polarization independence and incident angle insensitivity. Also, its complementary structure, i.e., using periodically T-shaped strip-patterned graphene, is investigated to design another dual-band abso

Wireless power transfer (WPT) technology has played a vital role in the rapid development of biomedical devices. While several single methods to improve WPT efficiency have been reported, the lack of integrality in these single methods limits the effect of the improvements. In this investigation, we analyze the physical process of a typical WPT scenario and find that the high propagation loss consisting of in-tissue attenuation and interface reflection degrades the WPT performance. A systematic

In this paper, we proposed a novel multifunctional reflectarray (RA) element which consists of resistor layer, switchable ground plane (SGP) layer and ground layer. The SGP consists of a frequency selective surface (FSS) and four PIN diodes. By switching the status of diodes, the SGP operates as ground or transparency to the incident waves thus the distance between the resistor layer and the ground is changed accordingly, which makes the incident power reflected or absorbed by the proposed RA el

With an unbroken metallic rim as the primary antenna and a 3-D printed planar inverted-F antenna (PIFA) connected with 50 Ω load as a branch, a multi-band antenna for smartwatch wearable device is proposed. The overall dimensions size of the design is 47×42×5 mm 3 . With the electromagnetic coupling between rim and PIFA branch, the operation bandwidth of the proposed antenna includes 1470–3600 MHz and 4800–6000 MHz which can cover GPS/DCS/PCS/UMTS2100/LTE2300/LTE2500/WLAN2.4G/Bl uetooth/WiMAX/W

A method for direction of arrival (DOA) estimation and object localization based on 1-bit time-modulated reflectarray (TMRA) is presented. The multi-harmonic multi-beam (MHMB) characteristic of 1-bit TMRA is analyzed firstly to reveal the mapping relationship between target’s angular feature and received spectrum feature. Then the operating principle and perception procedures for single and multiple targets scenarios are discussed in detail. Benefited from the mapping relationship, the proposed

In this paper, a 1-bit ultra-wideband reconfigurable reflectarray (RRA) element with improved angular stability is proposed. Based on the magneto-electric (ME) dipole, a novel central-patch probe structure is introduced, wherein two diodes are connected to opposite sides of the probe to control the two resonant modes. This configuration yields a fully symmetric RRA element, which balances and stabilizes the current distributions associated with both resonant modes, thereby enabling an ultra-wide

A broadband dual-polarized quad-ridged horn (QRH) antenna covering 2–14 GHz is proposed for antenna measurements and electromagnetic compatibility (EMC) testing. To achieve dual-port broadband impedance matching, a metallic ring-shaped matching block and two metallic bridges are incorporated into the feeding cavity. Additionally, the ridge profile is optimized using a fourth-order Bezier curve to ensure smooth impedance transitions, while the sidewall structure is shortened to mitigate radiation

While time-modulated reflectarrays (TMRAs) exhibit flexible beam control capabilities, they often operate at harmonic frequencies, which weakens their practicality. A method is proposed that enables the 1-bit TMRA to achieve beamforming at the carrier frequency. Specifically, four basic control time sequences (BCTSs) are introduced to simultaneously and independently generate an equivalent reflection amplitude-phase distribution, overcoming the limitation of amplitude-only control at the carrier

Although time-modulated metasurfaces (TMMS) possess flexible beam manipulation capability, they often operate at harmonic frequencies, which weakens their practicality. To solve this problem, a method enabling TMMS to achieve beam-forming at the carrier frequency is proposed and investigated. Specifically, the phase is controlled by a reconfigurable metasurface (MS), and additional time modulation (TM) amplitude excitation is introduced by utilizing an anti-phase modulation time sequence (APMTS)