The inverted-F antenna height effects on bandwidth

The inverted-F antenna is widely used in mobile applications due to its simple design, flexibility, low cost and reliable performance. The paper studies the relationships between antenna impedance bandwidth and its vertical dimension (height) based on measurements. The measurement results indicate the antenna SWR bandwidth increases nearly linearly with the antenna height. Increasing the antenna height increases the antenna area, resulting in reduced antenna Q value which is inversely proportional to the antenna bandwidth. So, for practical applications, the best way to increase antenna bandwidth is to maximize the antenna area (or volume for 3D antenna structures) within a given physical constraint. For the studied 2D inverted-F antenna implementation the height parameter has to be at least 11 mm to cover the 800 MHz band, while 3 mm covers the PCS band with a good margin.