Measurements of the Cross-Loop Antenna Patterns in High-Frequency Surface Wave Radars

In this letter, measurements of the cross-loop antenna patterns in the Ocean State Measuring and Analyzing Radar type S (OSMAR-S) for monitoring ocean environments are discussed. First, the patterns of the cross-loop antenna are measured by using a moving transponder. The results are not so good, as expected, due to the unstable transmitting signals and impacts of the environments. Then, an improved measurement method of the cross-loop antenna patterns is presented. The transmitting antenna is fixed, and the cross-loop antenna is fixed on a turntable and rotated with it to receive signals coming from different directions. In addition, the cross-loop antenna is connected to capacitors to resonate at the operating frequency. Then, the receiving signals of the operating frequency are strengthened, and the effects of environment are reduced. The near-field and far-field experiments are performed, and the measured patterns are of “8” shapes. Impacts of metal obstacles are also discussed, which provide a basis for evaluating antenna erection of the OSMAR-S. The ocean currents calculated from the patterns measured by the method in this letter are compared with that measured by an acoustic Doppler current profiler. They are in a good agreement, which proves the validation of the measurement method.

[1]  Kun-Chou Lee,et al.  Reducing the array size for DOA estimation by an antenna mode switch technique , 2012 .

[2]  Jeffrey D. Paduan,et al.  Remotely sensed surface currents in Monterey Bay from shore-based HF radar (Coastal Ocean Dynamics Application Radar) , 1996 .

[3]  Alexis Berne,et al.  Quantification and Modeling of Wet-Antenna Attenuation for Commercial Microwave Links , 2013, IEEE Geoscience and Remote Sensing Letters.

[4]  David Lyzenga,et al.  Surface-Wavefield Estimation From Coherent Marine Radars , 2010, IEEE Geoscience and Remote Sensing Letters.

[5]  Gianfranco Fornaro,et al.  Estimation and Compensation of Phase Shifts in SAR Focusing of Spotlight Data Acquired With Discrete Antenna Steering , 2014, IEEE Geoscience and Remote Sensing Letters.

[6]  Hao Zhou,et al.  Analysis of the higher order Bragg scatter in HF radar , 2013 .

[7]  B. Lipa,et al.  Least-squares methods for the extraction of surface currents from CODAR crossed-loop data: Application at ARSLOE , 1983, IEEE Journal of Oceanic Engineering.

[8]  B. J. Lipa,et al.  Using antenna patterns to improve the quality of SeaSonde HF radar surface current maps , 1999, Proceedings of the IEEE Sixth Working Conference on Current Measurement (Cat. No.99CH36331).

[9]  Hao Zhou,et al.  Ionospheric Clutter Suppression in HFSWR Using Multilayer Crossed-Loop Antennas , 2014, IEEE Geoscience and Remote Sensing Letters.

[10]  Li Si-ming.  Sea states observation with a portable HFSWR during the 16th Asian Games Sailing Competition , 2012 .

[11]  Libe Washburn,et al.  Evaluating Radial Current Measurements from CODAR High-Frequency Radars with Moored Current Meters , 2004 .

[12]  D. Barrick,et al.  Correcting for distorted antenna patterns in CODAR ocean surface measurements , 1986 .

[13]  F. Chavez,et al.  Calibration and Validation of Direction-Finding High-Frequency Radar Ocean Surface Current Observations , 2006, IEEE Journal of Oceanic Engineering.

[14]  M. Soljačić,et al.  Wireless Power Transfer via Strongly Coupled Magnetic Resonances , 2007, Science.

[15]  Bernard Uguen,et al.  Improving the Azimuthal Resolution of HFSWR With Multiplicative Beamforming , 2012, IEEE Geoscience and Remote Sensing Letters.

[16]  B. Lipa,et al.  SeaSonde Radial Velocities: Derivation and Internal Consistency , 2006, IEEE Journal of Oceanic Engineering.

[17]  Ijaz Mansoor Qureshi,et al.  Ambiguity Function of Phased–MIMO Radar With Colocated Antennas and Its Properties , 2014, IEEE Geoscience and Remote Sensing Letters.