A. Sahaya Anselin  Nisha, T.  Jayanthy, 
    Design and Analysis of Multiband Hybrid Coupled Octagonal Microstrip Antenna for Wireless Applications,
    Journal of Engineering and Applied Sciences,
    Volume 7,Issue 7,
    2012,
    Pages 428-431,
    ISSN 1816-949x,
    jeasci.2012.428.431,
    (https://makhillpublications.co/view-article.php?doi=jeasci.2012.428.431)
    Abstract: A novel octagon shaped hybrid coupled microstrip antenna for 
  multiband operation is proposed. By exciting two orthogonal modes by 90° 
  time phase difference in hybrid coupling circular polarization is obtained. 
  The gain is enhanced by tapering at the end of hybrid coupling. The design simulation 
  is done using method of moment based software. The proposed antenna is resonating 
  in the frequency range of 2-4 GHz. Hybrid coupled octagonal patch antenna is 
  having gain of 9.11 dB and the directivity of 8.98 dB. Power radiated by this 
  antenna is 0.038 W.
    Keywords: FR4 substrate;hybrid coupler;multiband operation;network analyzer;octagonal shape;patcho antennas