Design and Simulation of Folded Arm Miniaturized Microstrip Low Pass Filter

In this paper we presented two simple designsChebyshev 3-pole microstrip stepped-impedance low-pass filter in L-band (1 GHz) and folded arm microstrip lowpass filter which is widely being implemented in GPS systems, mobile phones and defence telemetry. Various shapes are designed, simulated and frequency is tuned by altering the stub size and its position. According to the shape of the devices these two filters can be implemented. These two filters are designed for 1 GHz cut-off frequency at -3dB with a passband ripples less than 0.1dB and it shows sharp stopband 1 GHz - 4.9 GHz. Effective permittivity of the substrate is 10.8 and height 1.27 mm. The stepped impedance LPF is a traditional filter and folded arm filter is also a stepped impedance LPF but its inductive arm is bent at 90°. Folded arm filter is the miniaturized form of the traditional LPF. The miniaturized LPF gives the same performance as the traditional stepped impedance LPF. The filter is miniaturized by folding its inductive arm at 90° and its dimensions are optimized. Area of folded arm lowpass filter is reduced by 27.9% with respect to the traditional stepped impedance lowpass filter. These LPF filters are designed and simulated on Ansoft-HFSS platform. Its gives the satisfactory results between theoretical and simulated ones.