A series of non-stoichiometric BaK$_{1-x}$Na$_x$Gd$_3$Fe$_5$O$_{15}$ ($x = 0.00$, 0.10, 0.20, 0.30) tetragonal tungsten bronze (TTB) ceramics were synthesized via solid-state reaction, cold sintering at 150$^\circ$C, and assisted sintering at 400$^\circ$C and 500$^\circ$C. XRD confirmed single-phase TTB formation. Enhanced crystallinity and sharper diffraction peaks with increasing assisted sintering temperature indicated improved grain growth and ordering. Density measurements revealed Na$^+$ substitution combined with salt-assisted processing significantly influenced densification, with BKGF-1NST$_2$ achieving the highest bulk density of 4.32g/cm$^3$. Dielectric characterization showed fre... More >