A Study of 28 GHz, Planar, Multilayered, Electrically Small, Broadside Radiating, Huygens Source Antennas

Two 28 GHz, planar, electrically small Huygens source antennas are presented that are broadside radiating and are based on multilayer PCB technology. The designs seamlessly integrate electric Egyptian axe dipole and magnetic capacitively loaded loop near-field resonant parasitic elements with a coax-fed dipole radiator. Both linearly polarized (LP) and circularly polarized (CP) systems are demonstrated. The simulations of the LP system indicate that it is electrically small: ka = 0.961; has peak realized gains and front-to-back ratios (FTBRs) in the range from, respectively, 3.77 to 4.54 dBi and 7.16 to 33.92 dB; and radiation efficiencies higher than 81.14% over its entire 2.14%, -10-dB fractional impedance bandwidth (FBW-10dB). A prototype was fabricated and tested; the measured and simulated results are in good agreement. The CP system exhibits similar properties: ka = 0.942; 1.41% FBW-10dB with a 0.47% 3-dB axial ratio fractional bandwidth; and peak realized gain, FTBR, and radiation efficiency values equal to 2.03 dBi, 26.72 dB, and 73.4%, respectively. To confirm their efficacy for on-body applications, the specific absorption rate values of both the LP and CP Huygens source antennas were evaluated and found to be very low.