The experimental validation of reduced grating lobes in a seven-element, hexagonal, scanning phased array antenna with the one-wavelength element spacing is presented. The base element of the array is a single-layer, dual-mode antenna with self-scanning and nulling properties. For the selected scan angle of -30°, the required microstrip transmission line based feeding network, consisting of ring hybrids, power splitters, and branchline couplers, are designed and developed. A prototype of the complete array and feeding network was fabricated and successfully tested to show the effectiveness of the grating lobe reduction method using the dual-mode antenna elements in scanning phased array antennas with the one-wavelength element spacing.
2. Mailloux, R. J., Phased Array Antenna Handbook, 2nd Ed., Artech House, Norwood, MA, USA, 2005.
3. Balanis, C. A., Antenna Theory: Analysis and Design, 4th Ed., Wiley, Hoboken, 620 NJ, USA, 2016.
4. Helander, J., D. Tayli, and D. Sjoberg, "Multi-port element for grating lobe suppression in sparse VHF phased array radars," IEEE Trans. Antennas Propag., Vol. 67, No. 10, 6667-6671, Oct. 2019.
5. Tu, X., G. Zhu, X. Hu, and X. Huang, "Grating lobe suppression in sparse array-based ultra-wideband through-wall imaging radar," IEEE Antennas Wireless Propag. Lett., Vol. 15, 1020-1023, Oct. 2016.
6. Lu, B., S. X. Gong, S. Zhang, Y. Guan, and J. Ling, "Optimum spatial arrangement of array elements for suppression of grating-lobes of radar cross section," IEEE Antennas Wireless Propag. Lett., Vol. 9, 114-117, Feb. 2010.
7. Bianchi, D., S. Genovesi, and A. Monorchio, "Randomly overlapped subarrays for reduced sidelobes in angle-limited scan arrays," IEEE Antennas Wireless Propag. Lett., Vol. 16, 1969-1972, Apr. 2017.
8. Krivosheev, Y. V., A. V. Shishlov, and V. V. Denisenko, "Grating lobe suppression in aperiodic phased array antennas composed of periodic subarrays with large element spacing," IEEE Antennas Propag. Magazine, Vol. 57, No. 1, 76-85, Feb. 2015.
9. Brockett, T. J. and Y. R.-Samii, "Subarray design diagnostics for the suppression of undesirable grating lobes," IEEE Trans. Antennas Propag., Vol. 60, No. 3, 1373-1380, Mar. 2012.
10. Haupt, R. L., "Reducing grating lobes due to subarray amplitude tapering," IEEE Trans. Antennas Propag., Vol. 9, No. 8, 846-850, Aug. 1985.
11. Bavaro, V., G. Caliano, and M. Pappalardo, "Element shape design of 2-D CMUT arrays for reducing grating lobes," IEEE Trans. Ultrason., Ferroelec., Freq. Contr., Vol. 55, No. 2, 308-318, Feb. 2008.
12. Hansen, R. C. and G. G. Charlton, "Subarray quantization lobe decollimation," IEEE Trans. Antennas Propag., Vol. 47, No. 8, 1237-1239, Aug. 1999.
13. Skobelev, S. P. and P.-S. Kildal, "Blindness removal in arrays of rectangular waveguides using dielectrically loaded hard walls," IEEE Trans. Antennas Propag., Vol. 46, No. 4, 546-550, Apr. 1998.
14. Feng, B.-K. and D. C. Jenn, "Grating lobe suppression for distributed digital subarrays using virtual filling," IEEE Antennas Wireless Propag. Lett., Vol. 12, 1323-1326, Oct. 2013.
15. Iqbal, Z. and M. Pour, "Grating lobe reduction in scanning phased array antennas with large element spacing," IEEE Trans. Antennas Propag., Vol. 66, No. 12, 6965-6974, Dec. 2018.
16. Iqbal, Z., T. Mitha, and M. Pour, "A self-nulling single-layer dual-mode microstrip patch antenna for grating lobe reduction," IEEE Antennas Wireless Propag. Lett., Vol. 19, No. 9, 1506-1510, Sept. 2020.
17. Pozar, D. M., Microwave Engineering, Wiley, Hoboken, NJ, 2012.
18. Lim, J.-S. and S.-Y. Eom, "A new 3-way power divider with various output power ratios," IEEE MTT-S International Microwave Symposium Digest, Vol. 2, 785-788, San Francisco, CA, USA, Jun. 17-21, 1996.
19., High Frequency Structure Simulator (HFSS 18.0), Canonsburg, PA, USA, ANSYS, 2018.