Wideband tunable meander-line loaded antenna with dual-mode capability in V/UHF frequencies

Wideband and multi-band antennas which have small physical sizes are interesting in many wireless applications. In this paper, a wideband meander-line loaded antenna with frequency tunable capability in V/UHF band is introduced. Considering VSWR <; 3:1, the proposed antenna covers most of 100 to 600 MHz frequency range in 4 states with dual-mode operation capability at 100 to 140 MHz and 515 to 570 MHz. Spherical structure of the antenna includes a coaxially-fed planar monopole and a meander-line loaded cap. Radiation pattern of the antenna is omni-directional in low frequencies and almost omni-directional in higher frequencies. The antenna has small dimension and can be enclosed by a sphere with radius of 30 cm.