Abstract |
In this paper, a fractal based complementary split ring resonator (CSRR) has
been introduced as a defected ground structure (DGS) in the ground plane of a
dual-mode microstrip BPF to produce a new compact filter with dual-band
response. The conventional double square ring resonator structure is modified
such that its inner ring is made with a fractal shape instead of a square.
Measured and simulation results show that the resulting filter offers a dual
passband response; the higher passband is attributed to the dual mode microstrip
ring structure, while the lower passband is as a result of the embedded CSRR DGS
structure. In addition, the results show that the position of the lower passband
could be varied, to a certain extent, without affecting the position of the
higher passband by applying higher fractal iteration levels to the inner split
ring. These features, together with the compact size the proposed filter offers,
make it suitable for use in a wide variety of dual-band communication
applications. Measured results, carried out on three filter prototypes, have
been found in agreement with those theoretically predicted. |