Y. E. Masrukin, N. Hassim, Z. Zakaria, N. S. A. S. Ali, and M. S. A. M Noh, “New Compact Dual-Band Bandpass Filter Using Stepped Impedance Resonator and U-Shaped Microstrip Structure”, JTEC, vol. 9, no. 2-8, pp. 99–102, Sep. 2017.