Electrically small antennas with dimensions down to one-fifteenth and one-thirtieth of wavelength

This paper presents two electrically small meander line antennas operating at 915 MHz. The first antenna has dimensions λ₀/30 by λ₀/30. It is constructed from a Vivaldi antenna whose two edges are connected through a meander line. The feeding is achieved via a slot line excited by a microstrip located at the backside of the substrate. The antenna has gain, efficiency and bandwidth of -3.75 dBi, 31%, and 28 MHz (3%) respectively. The size of the second antenna is λ₀/15 by λ₀/15. It consists of two antennas of the first design which are placed back-to-back. This antenna has gain, efficiency and bandwidth of -0.3 dBi, 76%, and 73 MHz (8%) respectively.