From: On the performance of MIMO RFID backscattering channels
L= 1
L= 2
N = 1
e sin 2 θ g γ ̄ E 1 ( sin 2 θ g γ ̄ ) g γ ̄
e sin 2 θ g γ ̄ E 2 ( sin 2 θ g γ ̄ ) sin 2 θ g γ ̄
N = 2
− γ ̄ sin 4 θ + e sin 2 θ g γ ̄ E 1 ( sin 2 θ g γ ̄ ) sin 6 θ + γ ̄ e sin 2 θ g γ ̄ E 1 ( sin 2 θ g γ ̄ ) sin 4 θ ( g γ ̄ ) 3