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The article discusses second harmonic suppression using periodically loaded SSS Coupled-line filter. Spurious suppression in microstrip line filters have been obtained using floating grounds. Using periodical non-uniform microstrip coupled-lines, spurious rejection has been achieved. The number of periodically loaded cells 'p' and the values of the capacitors C in each coupled-line section can be properly chosen to achieve the desired harmonic suppression. Based on the filter specifications, a standard synthesis procedure is used to calculate the required coupling coefficients. The equivalent circuit of the periodic cell is used along with the synthesized coupled-line dimensions to obtain the required loading capacitance for the suppression of the second harmonic.