A compact wide band filter based on the left handed material theory

A novel micro CRLH (composite right/left-handed) wide band filter based on Left handed material (LHM) theory was designed and fabricated. As a promising design, the length of the main part is only 1/20 compared to the working wavelength. It can be used to eliminate the noise in RF interconnect and other area. The phase shift in LHM is negative. This characteristic can decrease the phase delay. And also, the absolute value of phase constant will increase when frequency decrease at the left handed band (LH-band), which contribute to minimize the design. The other advantage of the LHM is that the phase constant will changed to the opposite direction, when the wavelength changed with the working frequency. This provides a negative feedback to the electric length, so the left handed region has a wider band width. Measurements results show that relative bandwidth (3 dB) of 8 cells is 71.42%. The relative bandwidth (3 dB) of 4 cells is 58.46%.