In this paper, an efficient microstrip low pass filter (LPF) using arrow-shaped resonators has been proposed. For attenuating undesired harmonics in stop band, stepped-impedance attenuators have been applied. To suppress components in frequency band of 6–10 GHz, two single-base high-impedance stubs have been exploited. To analyze the proposed structure accurately and define the role of each element in the filter, L-C equivalent circuit has been presented. Using this L-C equivalent model, poles and zeros of transfer function can be calculated and discussed. The structure design is based on reducing the coupling effect of elements on each other and neglecting these effects in obtaining the transfer function. Two symmetric arrow-shaped resonators with high-length basis provide 3-dB cut-off frequency as 1.447 GHz. The proposed filter has flat pass band with insertion loss as −0.08 dB and wide stop band with relative stop-band bandwidth (RSB) equal to 1.728. The figure of merit (FOM) is 113,355 which is much interesting compared to other similar works in this field as shown in simulation results.
