In this paper, a wideband 1-bit 12×12 reconfigurable beam-scanning reflectarray is designed, fabricated, and measured. The 1-bit reconfigurable element is realized by soldering PIN diode into a slotted metallic square patch. To enhance the bandwidth of 1-bit reconfigurable reflectarray, we choose the central frequency at 5.0 GHz whose phase shift is 200° where the maximum phase shift occurs. Phase difference within 180°± 20° is realized from 4.7 GHz to 5.3 GHz. Utilizing this wideband element, the 12 × 12 reconfigurable reflectarray antenna is fabricated and measured. A control board which can display phase shift distributions in real-time is designed to regulate all PIN diodes independently. Experimental results show that beam-scanning within ±50° can be achieved both in xoz- and yoz-plane at 5.0 GHz. Also, the measured results present that -1dB gain bandwidth is 8.4% from 4.85 GHz to 5.275 GHz.

A new wideband circularly polarized antenna using metasurface superstrate for C-band satellite communication application is proposed in this letter. The proposed antenna consists of a planar slot coupling antenna with an array of metallic rectangular patches that can be viewed as a polarization-dependent metasurface superstrate. The metasurface is utilized to adjust axial ratio (AR) for wideband circular polarization. Furthermore, the proposed antenna has a compact structure with a low profile of 0.07λ ₀ ( λ ₀ stands for the free-space wavelength at 5.25 GHz) and ground size of 34.5×28 mm ² . Measured results show that the -10-dB impedance bandwidth for the proposed antenna is 33.7% from 4.2 to 5.9 GHz, and 3-dB AR bandwidth is 16.5% from 4.9 to 5.9 GHz with an average gain of 5.8 dBi. The simulated and measured results are in good agreement to verify the good performance of the proposed antenna.

In this paper, a novel polarization-reconfigurable converter (PRC) is proposed based on a multilayer frequency-selective surface (MFSS). First, the MFSS is designed using the square patches and the grid lines array to determine the operational frequency and bandwidth, and then the corners of the square patches are truncated to produce the phase difference of 90° between the two orthogonal linear components for circular polarization performance. To analyze and synthesize the PRC array, the operational mechanism is described in detail. The relation of the polarization states as a function of the rotating angle of the PRC array is summarized from the principle of operation. Therefore, the results show that the linear polarization (LP) from an incident wave can be reconfigured to LP, right- and left-hand circular polarizations by rotating the free-standing converter screen. The cell periods along x- and y-directions are the same, and their total height is 6 mm. The fractional bandwidth of axial ratio (AR) less than 3 dB is more than 15% with respect to the center operating frequency of 10 GHz at normal incidence. Simultaneously, the AR characteristics of different incidence angles for oblique incidence with TE and TM polarizations show that the proposed PRC has good polarization and angle stabilities. Moreover, the general design procedure and method is presented. Finally, a circularly shaped PRC array using the proposed PRC element based on the MFSS design is fabricated and measured. The agreement between the simulated and measured results is excellent.

As it is well known, the bandwidth of antenna will decrease with the decrease of antenna size and this feature limits the design of compact Global Navigation Satellite System (GNSS) patch antenna (1.1–1.6 GHz). In this communication, a novel wideband technique based on the mode analysis on the shorting load patch antenna is proposed. By adjusting the position and the size of the shorting load structure, the dominant resonant mode of patch antenna(TM₁₀) is divided into two secondary modes and these two modes are combined together to form a wide operating band. It is proved that this new method has better bandwidth enhancement effect than the traditional methods. By utilizing this proposed method, a compact circularly polarization wideband patch antenna is designed for GNSS application, which has a small electrical size of only $0.2\lambda _{0}\times 0.2\lambda _{0}\times 0.05\lambda _{0.}$ ( $\lambda _{0}$ is the wavelength of low band in free space.) The simulated and measured results show that the proposed antenna has good and stable performance over the whole operating band, which means that it is quite an ideal compact antenna used for GNSS satellite navigation applications.

This paper proposes a new frequency-reconfigurable antenna (FRA) which consists of quasi-Sierpinski fractal dipoles integrating with a dual-band high-impedance surface (HIS). The antenna can operate in three frequency bands, i.e., X-band, Ku-band, and Ka-band, by changing the states of two switches. In order to achieve a low-profile design and good front-to-back radiation ratio, a dual-band HIS is presented as a reflector. The HIS is composed of an array of square patches with etching square slots, which has two in-phase reflection bands for X-band and Ku-band and can be viewed as an artificial magnetic conductor, while as a metallic electric conductor in Ka-band. So the antenna has a unified profile of 2 mm for different reconfigurable frequency bands. An ideal switch prototype of FRA was simulated, and practical PIN switch models of FRA and 2 × 2 FRA array with bias lines were fabricated and tested to verify the reconfigurable property of the proposed antenna.

A rectangular mushroom-like superstrate structure is proposed to design an antenna for dual-band wireless local area network (WLAN) applications. The proposed antenna consists of an array of mushroom-like rectangular patches and a planar slot antenna. Based on the dispersion diagram analysis, the proposed antenna can operate in two bands: The lower band is from 2.3 to 2.98 GHz, with -10-dB bandwidth of 25.8%, which is corresponding to zeroth-order resonant (ZOR) mode, and the upper band is from 5.02 to 5.84 GHz, with -10-dB bandwidth of 15.1% and average realized gain of 6.9 dB at boresight. The proposed antenna is feasible to cover the specification for dual-band WLAN applications in the 2.4-GHz (2400-2484 MHz) and 5-GHz (5150-5825 MHz) bands. Furthermore, the proposed antenna has a low profile of 4.2 mm and compact size of 33 ×30 mm ² , which is suitable for installation in wireless handheld devices. The simulated and measured results are in good agreement to verify the good performance of the proposed antenna.