DUAL BAND F-ANTENNA FOR EUROPE AND NORTH AMERICA

A single antenna for multiple bands are always beneficial from the design point of view. Here a single antenna which is fundamentally inverted F antenna is used, the uniqueness of the design is that , it uses trap technique to produce dual resonance from a single inverted F antenna . The trap used to block the current due to some frequencies and passes the current contributed by other frequencies. So in short , this trap is like a RF filter which has some passband as well as stop band. This trap approach uses a LC network to achieve this design goal .The two bands of interest are 865-870 MHz and 902-928 MHz .. The challenge of this design is that the frequency separation of the two bands is very small. In this case, and also the extra section for low frequency band is too small. Then, the influence of trap LC component variation due to tolerance to the two resonant frequencies is big, and so it is difficult to achieve good in band return loss within the LC tolerance. This is the main difficulty of this design. This issue is resolved by placing the low band section away from the end of the antenna. The antenna is designed on FR4 substrate material having thickness of 1.6 mm and hence it is a low cost solution which could use in various commercial applications which follows these bands.