Orientation Aware Intelligent 3-D Cubic Antenna System With Automated Radiation Pattern Reconfigurability

Abstract

With the era of Internet of Things (IoT), antennas that can adapt to different radio frequency environments have become highly desirable. These reconfigurable antennas must be compact to suit the futuristic IoT devices, be low cost for implementation on billions of devices, and be robust to the presence of nearby electronics. This paper demonstrates a novel 2.4 GHz 3D Cubic Antenna System, which comprises of a cube package with six microstrip patch antennas, one on each face. The system with embedded electronics, is aware of its orientation and reconfigures its radiation pattern automatically by switching ON the appropriate patch antenna for a focused communication with a boresight receiver. Alternately, if the position of the receiver is unknown, a quasi-isotropic radiation pattern can be achieved by providing the right phase conditions to all the patches to radiate simultaneously. The ground plane of the antennas provides a shield between the radiators and the electronics. In the focused mode, 10 dB more power is received as compared to the quasi-isotropic mode, which results in an energy efficient communication. While the quasi-isotropic mode provides an all-around radiation coverage with a gain variation of 6.4 dB for the entire 3D sphere, which is one of the best reported experimental value in literature for IoT compatible antenna systems.INDEX TERMS Intelligent antenna, electromagnetic shielding, automated reconfiguration, quasi isotropic radiation, switched beam antenna.

Fully Printed 3-D Antennas With Wideband Radiation Isotropy Based on Annular Currents Models

“…By analogy, we calculate the gain variation of the combination of two orthogonal annular currents with 90 • phase difference between them (Fig. 2(c)) using formulae (1)(2)(3)(4)(5)(6)(7)(8). The gain variation, in this case, is equal to 2.1 dB.…”

“…These antennas are also attractive for energy harvesting, radio frequency identification (RFID) [4], flood monitoring [5], marine animal monitoring [6], etc. The huge volume of IoT devices requires antennas to be compact and minimal cost, which can both be fulfilled with three-dimensional (3D) antenna-in-package (AiP) and additive manufacturing technologies [7]. The global system for mobile communication (GSM) frequency band is commonly preferred for IoT network connection due to its widespread global infrastructure [8].…”

“…The GSM900 band operational bandwidth = 880.0 -915.0 MHz for uplink and 925.0 -960.0 MHz for downlink, hence antennas need to maintain their isotropic radiation pattern across the entire 8.7% bandwidth. In the literature, most previous designs have focused on antenna isotropy only at a single frequency without considering the isotropic radiation within a bandwidth [2], [3], [4], [5], [6], [7], and their reported impedance bandwidth is also narrow (< 9%). While some designs aimed at dual-band operation [1], [9], [10], [11], [12].…”

“…Finally, the antennas were realized with standard subtractive manufacturing technologies, which also makes them unsuitable for IoT applications where high throughput and low cost manufacturing is required. On the contrary, additive manufacturing, such as the fully printed fabrication process, for the design of high-performance antennas is attractive and promising, which is low-cost and avoids material wastage [5], [6], [7]. Specifically, the antenna substrates can be 3D printed, while the metallic pattern could be realized through screen printing or inkjet printing.…”

Post-Fabrication Technique to Manage Material Variations in 3-D Printed Microstrip Antenna Substrates

“…Because of the speed of printing, diversity of printed materials, low cost, reduced material wastage, and ability to develop complex geometries, 3D printing is becoming a preferred fabrication technique and is replacing conventional subtractive techniques, such as lithography and micromachining. In addition to its utility in various fields, a wide range of radio frequency (RF) components, such as antennas [2], [3], [4], [5], [6], [7], [8], [9], [10], [11], [12], absorbers [13], [14], couplers [15], filters [16], frequency-selective surfaces [17], diplexers [18], lenses [19], [20], [21], and waveguides [22], have been produced using 3D printing approaches.…”