Leaf-Shaped Planar Inverted Cone Antenna (Leaf-Shaped PICA)
Image of the Leaf-Shaped Planar Inverted Cone Antenna (Leaf-Shaped PICA).

PICAs are planar antennas with a semi-elliptical base and an inverted top installed above a ground plane. These antennas provide ultra-wideband (UWB) performance with radiation patterns similar to other monopole disc antennas.

The addition of three holes in the radiating element of the standard PICA reduces the overall size of the antenna, by changing the current distribution on the radiating element surface. This size reduction is achieved, while maintaining an extremely wide impedance bandwidth.

The holes give the radiating element a leaf-like appearance, hence the name of the structure.

Although the impedance performance of the leaf-shaped PICA is slightly worse in the lower portion of the band, the width of the leaf is somewhat reduced from the original width of the standard PICA. The addition of a dielectric layer as part of the ground plane would also efficiently effect the impedance matching, since it varies the capacitances in the multiresonance circuit of the input impedance.

Typical reflection coefficient

The bandwidth of the structure is limited by the radiation pattern performance, since the azimuth radiation pattern does not remain omnidirectional at all frequencies. This performance problem may be addressed by improving the structural asymmetry, e.g. by adding a second orthogonal radiating plate.

Total gain: fmin, 4.5fmin and 9fmin