A Compact Single-Element Pattern Reconfigurable Antenna With Wide-Angle Scanning Tuned by a Single Varactor

Abstract

In this paper, we propose a convenient fixed-frequency beam steering method, using a single patch antenna controlled by only one electronically tunable component. The antenna is based on coupled-mode patch antenna (CMPA) [1] that is capable to scan the beam as the function of frequency. A ground-etched slot loaded with one varactor diode is tuned to be capacitive, resonant, or inductive. In order to test broader tuning range, two kinds of varactors with the ranges of 9.24 pF-1.77 pF and 2.67 pF-0.63 pF are implemented respectively. By analyzing how the loaded slot affects the cavity modes and fields, we demonstrate how the voltage bias tunes the frequency responses and steers beam of the antenna. Perturbed by the loaded slot, the frequency response of the antenna shifts from center frequency of 2.35 GHz with the bandwidth of 4.26% down to the band centered at 2.3 GHz with the bandwidth of 4.35%. The maximum scanning range is realized at around 2.29 GHz where the measured main beam continuously scans from −34 • to +32 • when the varactor with lower tuning range is used and biased. Meanwhile, the main beam of 2.35 GHz scans from +32 • to +54 • when the higher-range varactor is biased. The proposed single-element antenna is able to maintain high gain and efficiency that are comparable to a regular patch antenna with same size and substrate.

A single patch antenna with dual pairs of coupled modes forwide‐anglefrequency beam scanning

“…Compared with the forward or backward beam-scanning antennas, [10][11][12][13] the proposed one can achieve both backward and forward beam scanning, but with low gain at the first operation band because of small electric size of the radiator. Compared with the backward-to-forward beam-scanning antenna, 14 the proposed design shows larger beam-scanning range as well as no extra voltage-controlled structure. Compared with the backward-to-forward beam-scanning antenna, 15 the proposed antenna can realize continuous beam scanning capability from backward to forward while maintaining higher gain and complete ground.…”

“…Since the odd TM 10 mode will change to the even TM 10 mode at a fixed frequency by increasing the bias voltage, 30° backward beam‐scanning range can be realized at 28 GHz but with reduced operation frequency range. In Reference 14, a varactor‐loaded slot on the ground is adopted to attain 66° beam scanning from backward to forward direction at 2.29 GHz. In Reference 15, a pin diodes‐loaded slot is utilized on the ground to change the effective form of the ground, which achieve ±78° wide‐angle discrete beam scanning at 2.4 GHz without requiring coupled mode.…”

Wide-Band Directional Cavity Antenna With Low Scanning Loss for Wlan

“…So, the coverage of the phased array antennas with pattern integrity is limited. Instead of using phase shifters to steer the radiation, pin diodes [5], varactor diodes [6], RF-MEMS switches [7] can also be used to steer the beam. But the extra bias lines needed for their operation make the antenna design more complex.…”

Design and Experimental Analysis of Multiband Compound Reconfigurable 5G Antenna for Sub‐6 GHz Wireless Applications

“…In [17], a 2.45 GHz pattern reconfigurable antenna for wireless sensor network (WSN) applications is introduced, which can switch the beam along 0°and ±80°. A compact single-element pattern reconfigurable antenna is reported in [18], with a beam scanning range of -34°to +32°at 2.29 GHz. Some other pattern reconfigurable antennas are presented in [19][20][21], which use different methods of pattern reconfigurability, i.e., complementary split ring resonators (CSRR) on the ground, switches with dielectric resonator, and microelectromechanical switches (MEMS) with coupling cells, respectively.…”