Comparative Analysis of Stepped Impedance with Open and Short Circuited Stub Microstrip Low Pass...

GRD Journals- Global Research and Development Journal for Engineering | Volume 3 | Issue 6 | May 2018 ISSN: 2455-5703

Comparative Analysis of Stepped Impedance with Open and Short Circuited Stub Microstrip Low Pass Fractal Filter Ranjeet Kumar Department of Electronics & Communication Engineering Maharana Pratap College of Technology, Gwalior

Pankaj Singh Tomar Department of Electronics & Communication Engineering Maharana Pratap College of Technology, Gwalior

Abstract This paper proposed a comparison of stepped impedance fractal low pass filters at 1 GHz with open stub and short-circuited stub. Sierpinski carpet fractals used to reduce filter size and develop low profile filters. Fractal elements or arrays are designed with the concept of self-similarity to achieve sharper cut off point. 1 GHz low pass filter is used for long range communication and smart phone communication for IOT application. Keywords- Fractal, Chebyshev Response, Stepped Impedance Low Pass Filter, Open Circuited Stub, Short Circuited Stub

I. INTRODUCTION Filters play significant roles in many RF/microwave applications. Filters are used to select or detain the RF/microwave signals within assigned spectral limits. They are used to separate or combine different frequencies. In current scenario of wireless communication filter require higher performance, smaller size, lighter weight, and lower cost. To achieve these requirements, we design a Sierpinski carpet [1-2] fractal filter. The general form of low pass filter may consist of series inductors and capacitor which is frequently found in many applications for direct current or to block the dc. In design and realization of microstrip filters, short section of transmission line or stub, whose length is much smaller than a quarter of guided wavelength are the most common components [3]. A small open circuited loss less microstrip line stub is equivalent to shunt capacitor and similarly small shortcircuited line is equivalent to shunt inductor [4]-[7]. For a more selective low pass filter, more of such elements are required. The element values for the low pass prototype shown in figure 1 with Chebyshev response at pass band ripple factor LAR= 0.1 dB, characteristic impedance Zo = 50Ω, are taken from normalized values gi i.e. g1, g2, g3, g4…… gn. The components L & C are realized by high and low impedance microstrip stub respectively. The values of different inductance Li and capacitance Ci are obtained from the design equations, as Li = (Zo/go) (2c/2πfc) g1 (1) Ci = (go/Zo) (2c/2πfc) g2 (2)

Fig. 1: Prototype of low pass filter

Fig. 2: Microstrip stepped impedance low pass filter

For width calculation microstrip for inductance

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Comparative Analysis of Stepped Impedance with Open and Short Circuited Stub Microstrip Low Pass Fractal Filter (GRDJE/ Volume 3 / Issue 6 / 009)

(3)

For width calculation of microstrip for capacitance (4)

Guide wavelength

(5)

Effective dielectric constant

Physical length (in mm) of the high and low impedance lines (inductance and capacitance respectively) with short circuited stub [4] is calculated by using the formulae

Physical length (in mm) of high and low impedance open circuited stub lines [4] (inductance and capacitance respectively) is calculated by using the formulae

Where Land C are the required element values of lumped inductors and capacitors respectively.

II. FILTER DESIGN SPECIFICATION AND CALCULATION In this section the design of low pass filter at 1 GHz cutoff is considered. For the proposed design shown in figure 3 and figure 9 which consists of short-circuited stub (grounded line) and open circuited respectively; the following parameters are considered: g1 =g3=1.0316, g2= 1.1474 Cut-off frequency, fc = 1 GHz. Relative Dielectric Constant, εr = 4.6 Loss tangent = 0.001 Height of substrate, h = 1.27 mm Characteristic Impedance ZO = 50 Ω Characteristic impedance of high impedance line (ZOL) = 95 Ω Characteristic impedance of low impedance line (ZOC) = 33 Ω The step impedance microstrip low pass filter has been designed using the above equations and parameters. Length and width of microstrip low pass filter elements are calculated using the above design equations for the above parameters and listed in table 1 and table 2. Table 1: Design parameters of microstrip lines for a stepped-impedance low pass filter at 1 GHz Zc (8) λgi (mm) W (mm) L (mm)

εeff

Zo = 50 λg0= 161 W0 = 2.364 4 3.46 ZOL = 95 λgl = 169 WL = 0.6 24.125 3.15 Zoc= 33 λgc= 157 WC = 4.4 21.46 3.651

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Comparative Analysis of Stepped Impedance with Open and Short Circuited Stub Microstrip Low Pass Fractal Filter (GRDJE/ Volume 3 / Issue 6 / 009)

Table 2: Design parameters of microstrip lines for an open stub stepped-impedance low pass filter at 1 GHz Zc (8) λgi (mm)

W (mm) L (mm)

εeff

Zo = 50 λg0= 35.3 W0 = 2.364 4 3.46 ZOL = 95 λgl = 37.4 WL = 0.6 24.125 3.15 Zoc= 33 λgc= 33.9 WC = 4.4 15.68 3.651

III. IE3D LAYOUT AND SIMULATION RESULT OF STEPPED IMPEDANCE MICROSTRIP FRACTAL LOW PASS FILTER

The final 2-D layout and simulation result of Stepped impedance microstrip low-pass filter is shown in Figure 3 to 8. The results represent the magnitude response of Stepped impedance short circuited microstrip low-pass filter. The figure clearly showing the Return- loss and insertion-loss expressed in terms of S- parameters (S11, S21).

Fig. 3: Layout of a Stepped impedance (zero iteration) microstrip low-pass filter with short circuited stub

Fig. 4: Simulated result of S11, S21 parameter stepped impedance low pass filter with short circuited stub

Fig. 5: Layout of a Stepped impedance (first iteration) microstrip low-pass filter with short circuited stub

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Comparative Analysis of Stepped Impedance with Open and Short Circuited Stub Microstrip Low Pass Fractal Filter (GRDJE/ Volume 3 / Issue 6 / 009)

Fig. 6: Simulated result of S11, S21 parameter stepped impedance (first iteration) low pass filter with short circuited stub

Fig. 7: Layout of a Stepped impedance (second iteration) microstrip low-pass filter with short circuited stub

Fig. 8: Simulated result of S11, S21 parameter stepped impedance (second iteration) low pass filter with short circuited stub

IV. IE3D LAYOUT AND SIMULATION RESULT OF OPEN STUB STEPPED IMPEDANCE MICROSTRIP FRACTAL LOW PASS FILTER

Layout and simulated results of open stub low pass filter with iteration at 5 GHz cutoff frequency are shown Figure 9 to 14. The results represent the magnitude response of Stepped impedance open circuited microstrip low-pass filter. The figure clearly showing the Return- loss and insertion-loss expressed in terms of S-parameters (S11, S21).

Fig. 9: Layout of a Stepped impedance (zero iteration) microstrip low-pass filter with open circuited stub

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Comparative Analysis of Stepped Impedance with Open and Short Circuited Stub Microstrip Low Pass Fractal Filter (GRDJE/ Volume 3 / Issue 6 / 009)

Fig. 10: Simulated result of S11, S21 parameter stepped impedance (zero iteration) low pass filter with open circuited stub

Fig. 11: Layout of a Stepped impedance (first iteration) microstrip low-pass filter with open circuited stub

Fig. 12: Simulated result of S11, S21 parameter stepped impedance (first iteration) low pass filter with open circuited stub

Fig. 13: Layout of a Stepped impedance (Second iteration) microstrip low-pass filter with open circuited stub

Fig. 14: Simulated result of S11, S21 parameter stepped impedance (second iteration) low pass filter with open circuited stub

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Comparative Analysis of Stepped Impedance with Open and Short Circuited Stub Microstrip Low Pass Fractal Filter (GRDJE/ Volume 3 / Issue 6 / 009)

V. CONCLUSION In the proposed work design of lowpass filters at 1 GHz and 2.4 GHz have been presented. On the basis of analysis of various designs of stepped impedance fractal low pass filter with short and open circuited proposed. It is clear from result analysis that Scattering parameters considered for design evaluation are well within the range of high quality filter design. The proposed filters are expected to be used for L-band applications and also in GSM operation band (0.8≤f≤2.4 GHz) cellular mobile communication, 2.4 GHz low pass filter is used as wireless LAN (802.11G) and 1 GHz low pass filter is used for long range communication and smart phone communication for IOT application. Table 3: Comparision Table DESIGN-1

DESIGN-2

ITERATIONS

Stepped impedance (Ref at 1.2GHz)

Open stub (Ref at 1.2GHz)

Stepped impedance (Ref at 2.5GHz)

Open stub (Ref at 2.5GHz)

Zero iteration

-6.217dB

-6.004dB

-3.644dB

-3.508dB

1st iteration

-6.192dB

-5.997dB

-3.606dB

-3.489dB

2nd iteration

-6.169dB

-5.98dB

-3.604dB

-3.482dB

3rd iteration

-6.129dB

-5.945dB

-3.595dB

-3.464dB

REFERENCE [1] [2]

[3] [4] [5] [6] [7]

Douglas H. Werner', Randy L. Haup and Pingjuan L. Werne J., “Fractal Antenna Engineering: The Theory and Design of Fractal Antenna Arrays” IEEE Antennas and Propagation Magazine, Vol. 41, No. 5, October I999 D. H. Werner and S. Ganguly, “Fractal Antenna Engineering Research, “IEEE Trans. Antennas Propagation, Vol. 45, No.1, pp. 38-57, Feb 2003.J.L. Li, S.W. Qu and Q. Xue, "Compact Microstrip Lowpass Filter with Sharp Roll-off and Wide Stop-band,” Electronics Letters, Volume: 45, No. 2, pp.110-111, 2009. Jia-Sheng Hong and M. J. Lancaster, “Theory and Experiment of Novel Microstrip Slow-Wave Open-Loop Resonator Filters,”IEEE Transactions on Microwave Theory and Techniques, Vol. 45, Issue 12, Part 2, pp. 2358–2365, 1997 Vivek Singh Kushwah, Geetam S. Tomar & Sarita Singh Bhadauria “Designing Stepped Impedance Micro strip Low Pass Filter Using Artificial Neural network at 1.8 GHz” 2013 International Conference on Communication Systems and Networks Technologies. Yaqeen S. Mezaal, Halil T. Eyyuboglu & Jawad K. Ali, “New Microstrip Bandpass Filter Designs Based on Stepped Impedance Hilbert Fractal Resonators” IETE Journal of research Vol. 60, No. 3, pp. 257-264May-June 2014. Y.S. Mezaal, J.K. Ali & H.T. Eyyuboglu, “Miniaturised microstrip bandpass filters based on Moore fractal geometry” International Journal of Electronics, 2015 Vol. 102, No. 8, pp. 1306–1319. IE3D Software Developed by M/S Zeland Software Inc

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Comparative Analysis of Stepped Impedance with Open and Short Circuited Stub Microstrip Low Pass...

Published on Jun 8, 2018

GRD Journals

This paper proposed a comparison of stepped impedance fractal low pass filters at 1 GHz with open stub and short-circuited stub. Sierpinski carpet fractals used to reduce filter size and develop low profile filters. Fractal elements or arrays are designed with the concept of self-similarity to achieve sharper cut off point. 1 GHz low pass filter is used for long range communication and smart phone communication for IOT application. Citation: Pankaj Singh Tomar, Maharana Pratap College of Technology, Gwalior; Ranjeet Kumar ,Maharana Pratap College of Technology, Gwalior. "Comparative Analysis of Stepped Impedance with Open and Short Circuited Stub Microstrip Low Pass Fractal Filter." Global Research and Development Journal For Engineering 36 2018: 67 - 72.