Active seismic surveys, for the exploration of oil and gas reservoirs, are conducted using a huge network of geophone sensors (>10,000) covering a very large area and interconnected using seismic cables. Such cables enable reliable operation and fast data transfer, but account for a major percentage of the survey cost and limit its flexibility. In this paper, a wireless seismic data acquisition system that provides real-time data transmission for active seismic surveys is designed and implemented. A system that comprises a smart wireless sensor node and a gateway unit is demonstrated as a proof-of-concept. The smart wireless node comprises a geophone sensor, a high-resolution data acquisition system and a smart reconfigurable wireless communication module. The data acquisition system includes an electronic circuit for amplification and filtering, a single-board computer and a 24-bit analog-to-digital converter (ADC). The wireless communication module comprises a 2.4 GHz radio frequency (RF) transceiver connected to a pattern reconfigurable antenna. A microcontroller is employed to reconfigure the Yagi-Uda antenna to scan its radiation pattern in different directions and focus the radiated power in the direction of the nearest gateway. This high-gain directional antenna would allow communication between the sensor node and the gateway over a longer distance as compared with the monopole antenna conventionally employed in commercial wireless seismic systems. The proposed system, employing a reconfigurable antenna in the sensor node, has been implemented and tested and was able to successfully capture seismic data from the geophone sensor and transmit it wirelessly in real-time to the gateway unit, achieving a notable 25% enhancement in the communication range between the sensor node and the gateway. This communication range enhancement results in a significant 56% enhancement in the gateway's communication area coverage, when compared to similar systems that use conventional monopole antennas in their sensor nodes.
In this paper, a pattern reconfigurable printed Yagi‐Uda antenna with linear polarization is presented. The proposed design consists of three parts, including a driving element centered between two other parasitic elements. To achieve pattern reconfigurability, the approach of Yagi‐Uda configuration is employed, where the positions of the director and reflector are exchanged using PIN diodes. The proposed antenna employing six PIN diodes is designed to radiate the main beam at seven scanning angles (−60°, −40°, −20°, 0°, 20°, 40°, and 60°). The beam tilt depends on the size of the antenna's partial ground plane. The proposed design is simple in structure realized on a single substrate board of dimensions 75 × 70 mm2. The measured peak directivity obtained at various scanning angles is about 6.5 dB. The simulated and measured results are in good agreement. The proposed reconfigurable antenna is suitable for WiMAX applications operating around the frequency of 3.6 GHz.
Fifth‐generation millimeter‐wave devices with multiple antennas require minimal mutual interference for better overall performance. This article presents a simple but novel technique to improve the isolation between closely packed slot antenna arrays. A printed ridge gap waveguide (PRGW) structure is used to realize a low loss millimeter‐wave array's feeding mechanism. By optimally introducing a defective upper plate within the PRGW structure, the measured port isolation of the antenna elements is improved by 17 dB at 61.3 GHz. The antenna array is impedance matched to the feeding PRGW structure over a wide frequency range of 54–67 GHz. Moreover, the radiation patterns are consistent showing broadside radiation before and after introducing the defect in the PRGW structure. The fabricated prototype of the PRGW fed slot antenna array validated the predicted isolation and return‐loss bandwidths of the proposed radiating system.
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