Design of a low pass filter using rhombus-shaped resonators with an analytical LC equivalent circuit

In this paper, a new method is presented for the design of a low pass filter LPF based on an LC equivalent circuit. Firstly, new formulas are proposed to calculate an LC equivalent circuit of a rhombus-shaped resonator. Secondly, the transfer function and transmission zero of the rhombus-shaped resonator are extracted, based on the presented formulas. Then other rhombus-shaped resonators are designed, based on the extracted formulas. The proposed filter has a cut-off frequency with an attenuation level of 3 dB at 1.54 GHz. The obtained return loss and insertion loss in the pass band are 16 dB and 0.1 dB, respectively. The designed filter is fabricated on RT-5880 with 31 mil thickness.

___

  • [1] Hong JS, Lancaster MJ. Microstrip Filters for Rf/Microwave Applications. New York, NY, USA: Wiley, 2001.
  • [2] Pirasteh A, Roshani S, Roshani S. Compact microstrip lowpass filter with ultrasharp response using a squareloaded modified T-shaped resonator. Turkish Journal of Electrical Engineering & Computer Sciences 2018; 62 (4): 1736-1746.
  • [3] Roshani S, Golestanifar A, Ghaderi AH, Roshani S. Miniaturized LPF with sharp transition-band using semi-circle resonators. Applied Computational Electromagnetics Society Journal 2017; 32 (4): 344-351.
  • [4] Roshani S. A compact microstrip low-pass filter with ultra wide stopband using compact microstrip resonant cells. International Journal of Microwave and Wireless Technologies 2017; 9 (5): 1023-1027.
  • [5] Salehi A, Moloudian G, Setoudeh F. Design, simulation and manufacturing microstrip low-pass filter by wide stopband and changing fast situation from passing state to stopping. IETE Journal of Research 2018; doi: 10.1080/03772063.2018.1433079
  • [6] Tiwary AK, Gupta N. Performance of microstrip low-pass filter on electromagnetic band gap ground plane. IETE Journal of Research 2010; 56 (5): 230-234.
  • [7] Liu S, Xu J, Xu Z. Compact lowpass filter with wide stopband using stepped impedance hairpin units. Electronics Letters 2014; 51 (1): 1211-1214.
  • [8] Zhang B, Li SH, Huang J. Compact lowpass filter with wide stopband using coupled rhombic stubs. Electronics Letters 2015; 51 (3): 264–266.
  • [9] Xiao M, Sun G, Li X. A lowpass filter with compact size and sharp roll-off. IEEE Microwave and Wireless Components Letter 2015; 25 (120): 790-792.
  • [10] Karimi GH, Lotfi A, Siahkamari H. Design of microstrip lowpass filter with sharp roll-off using elliptical and radial resonators. Frequenz 2017; 71 (7): 349-356.
  • [11] Mousavi SMH, Makki SVAD, Siahkamari H. Design of microstrip lowpass filter using bend configuration with excellent sharpness in transition band. Frequenz 2016; 70 (5): 237-243.
  • [12] Palandoken M. Metamaterial-based compact filter design. In: Jiang XY (editor). Metamaterial, USA: IntechOpen, 2012.
  • [13] Pirasteh A, Roshani S, Roshani S. A modified class-F power amplifier with miniaturized harmonic control circuit. AEU-International Journal of Electronics and Communications 2018; 97: 202-209.
  • [14] Velidi VK, Sanyal S. Sharp roll-off lowpass filter with wide stopband using stub-loaded coupled-line hairpin unit. IEEE Microwave and Wireless Components Letters 2011; 21 (6): 301–303.
  • [15] Xu J, Ji YX, Wu W, Miao CH. Design of miniaturized microstrip LPF and wideband bpf with ultra-wide stopband. IEEE Microwave and Wireless Components Letter 2013; 23 (8): 397-399.
  • [16] Jiang S, Xu J. Compact microstrip lowpass filter with ultra-wide stopband based on dual-plane structure. Electronics Letters 2017; 53 (9): 607-609.
  • [17] Chen CHJ, Sung CHH, Su YD. A multi-stub lowpass filter. IEEE Microwave and Wireless Components Letter 2015; 25 (8): 532-534.
  • [18] Jiang SH, Xu J. Sharp roll-off planar lowpass filter with ultra-wide stopband up to 40 GHz. Electronics Letters 2017; 53 (11): 734-735.
  • [19] Li Q, Zhang Y, Li D, Xu K. Compact low-pass filters with deep and ultra-wide stopband using tri- and quad-mode resonators. IET Microwaves, Antennas & Propagation 2017; 11 (5): 743-748.
  • [20] Majidifar S, Ayati M. Design of a sharp response microstrip lowpass filter using taper loaded and radial stub resonators. Turkish Journal of Electrical Engineering & Computer Sciences 2017; 25 (5): 4013-4022.
  • [21] Majidifar S. High performance microstrip LPFs using dual taper loaded resonator. Optik-International Journal for Light and Electron Optics 2016; 127 (6): 3484-3488.