The two resonant modes of the simulated return loss of the
“winged” monopole have been combined together and its
bandwidth is increased to cover the range 1.31GHz to 2.46GHz
(61%), see Fig.2. To further extend its applications to a lower
band at 900MHz, two slots were added to the rectangular
monopole to increase its electrical length without increasing the
overall size of the antenna, shown in Fig. 1(b). By tuning the
size and position of the slots, a strong current can be excited
along the slots to resonate around 900MHz.
Fig.1. (a) Rectangular monopole and (b) with added wings and slots
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