A compact passive broadband hexagonal spiral antenna array for VHF remote sensing. - Richard J. Barton; Peter J. Collins; Paul E. Crittenden; Michael J. Havrilla; Andrew J. Terzuoli (IGARSS, 2007)

A Novel Method for Determining the R-Card Sheet Impedance Using the Transmission Coefficient Measured in Free-Space or Waveguide Systems. - Milo W. Hyde; Michael J. Havrilla; Paul E. Crittenden (IEEE Trans. Instrum. Meas., 2009)