Two-Ray Propagation

This example plots signal strength as function of range, compared to free space power spread.

using ..RadioPropagation
using Plots

c = 3e8;

transmit_height_m       = 2;
receive_height_m        = 10;
target_range_m          = LinRange(20, 100, 10000);
transmit_frequency_hz   = 3e9;
λ = c/transmit_frequency_hz;
Γ1 = -1;
Γ2 = -0.6;

F²( Γ ) = RadioPropagation.two_ray_propagation.( target_range_m, transmit_height_m, receive_height_m, transmit_frequency_hz, Γ );

F²1 = F²( Γ1 );
F²2 = F²( Γ2 );

f⁴_db( F² ) = 10*log10.( abs2.( F² ));

freespace_loss_db = 10 .*log10.(λ^2 ./( (4*π)^3 .*target_range_m .^4 ));
bias = freespace_loss_db[1]


plot1 = plot( target_range_m, f⁴_db.(F²1)+freespace_loss_db .-bias,
                xlabel  = "Range (one-way) [m]",
                ylabel  = "Two-way loss [dB]",
                title   = "Free-space versus two-ray propagation.",
                ylims   = (-30, 6),
                label   = "|F|⁴+L, Γ=-1",
                legend  = true,
                xaxis   =:log,
                dpi=300);
plot!(  target_range_m, f⁴_db.(F²2)+freespace_loss_db .-bias,
        label   = "|F|⁴+L, Γ=-0.6",
        xaxis   =:log );
plot!(  target_range_m, freespace_loss_db .-bias,
        label   = "L",
        xaxis   =:log );