the feed loop 40 which tends to decrease as the space between the two loops is decreased the impact on outer loop 30 from inner loop 50 is not significant provided that the spacing between the two loops is greater than 0 05 u03bb in practice the design of an antenna having a particular response is an iterative process requiring adjustments to the configuration of each antenna loop forming the antenna 10 and assessing the impact of each change on the overall performance of the antenna 10 the iterative process involves both manual and computer steps to assess the impact of a particular design change on the antenna 39 s characteristics such iterative steps are performed at a pre manufacture simulation stage and also once a prototype antenna has been fabricated the terminal impedance of the tri loop antenna 10 is determined not only by the feed loop 40 but also by configuration width length spacing of the parasitic loop 50 the width and length of the outer loop 30 will also have some influence on the terminal impedance but its effect will generally not be so pronounced as that of the parasitic loop the impedance matching of the antenna to the connected circuitry can be improved by adjusting the widths and circumferences of the individual loops and this process is.