A new compact nonuniform leaky-wave antenna (LWA) with left-handed elliptical polarization (LHEP), based on composite right/left-handed (CRLH) metamaterial operating in the range of 7-10.2 GHz is presented in the work. The nonuniform structure of a CRLH transmission line (TL) is realized by the placement of different configurations of inter-digital capacitor (IDC) in the form of sinusoid (SIN-IDC), on the top of metal wall of a half-mode substrate integrated waveguide (HMSIW). Balanced condition of the unit cells is provided by the change in slit width, amplitude and the number of SIN-IDC periods, as well as by relocation of two additional transition apertures arranged by both sides of SIN-IDC. Based on the known Hensen-Woodyard criterion, the optimal number of the unit cells was determined, when the gain coefficient varied from 7.5 to 9.8 dB in all of the operational range of antenna. The developed prototype of nonuniform CRLH LWA has the size of 8.1x115.2 mm. It is characterized by a continuous scan angle range equal to 117°. The maximum angle of rotation radiation pattern is -66° for backward radiation and +51° for direct radiation. The maximum efficiency of the antenna radiation is 85%, while the total one is 68%.