Compact WSN antennas of analytic geometry based on Chebyshev polynomials

Compact antennas shaped after the smooth sinusoidal curve have been studied in the past; their study revealed a good potential for integration into miniature devices. However, the sinusoid is hardly the only available smooth, analytic curve. This paper augments the field of analytic geometry antennas by introducing printed bent monopoles shaped after Chebyshev polynomials. The non-uniform sweeping of the proposed analytic expression produces a combination of inductive and capacitive (top-hat) loading for antenna miniaturization. Capacitive loading helps to maintain a large fractional bandwidth, while it produces smaller electrical sizes. Chebyshev antennas are highly efficient and function well with small ground planes. Their design is highly repeatable, since they are based on closed-form analytical expressions.