<p>This work presents a novel iterative optimization approach for multi-antenna multi-tag monostatic backscatter systems (MBS). The proposed method maximizes the collective communication rate (sum-rate) of multiple tags while incorporating constraints on transmission power, combiner design, and tag limitations. A closed-form solution is derived for the combiners, while beamforming vectors and backscattering coefficients are optimized through a two-step iterative algorithm. The block coordinate descent technique is employed to solve the optimization problem, where variables are updated sequentially while others are held constant. Furthermore, the model is simplified for low-SNR regimes, providing tractable benchmarks for performance evaluation. Extensive simulations demonstrate that the proposed iterative approach achieves superior performance compared with existing methods, resulting in a significant improvement in the communication rate within the MBS system.</p>