tfer_ehara.m

% TFER_EHARA    Evaluates the transfer function for a PMA in Case 1S as per Ehara et al. (1996).
% Author:       Timothy Sipkens, 2018-12-27
% 
% Inputs:
%   sp          Structure defining various setpoint parameters 
%               (e.g. m_star, V). Use 'get_setpoint' method to generate 
%               this structure.
%   m           Particle mass
%   d           Particle mobility diameter
%   z           Integer charge state
%   prop        Device properties (e.g. classifier length)
%
% Outputs:
%   Lambda      Transfer function
%=========================================================================%

function [Lambda] = tfer_ehara(sp, m, d, z, prop)

[tau, ~, ~, rs] = parse_inputs(sp, m, d, z, prop);
        % parse inputs for common parameters

%-- Estimate device parameter --------------------------------------------%
lam = 2 .* tau .* ([sp.alpha]' .^ 2 - ...
    [sp.beta]' .^ 2 ./ (rs .^ 4)) .* prop.L ./ prop.v_bar;


%-- Evaluate transfer function -------------------------------------------%
rho_s = (rs - prop.rc) ./ prop.del;
Lambda = ((1 - rho_s) + (1 + rho_s) .* exp(-lam)) ./ 2 .* ...
    and(1 < rho_s, rho_s<coth(lam ./ 2)) + ...
    exp(-lam) .* and(-1 < rho_s, rho_s < 1) + ...
    ((1 + rho_s) + (1 - rho_s) .* ...
    exp(-lam)) ./ 2 .* and(-coth(lam ./ 2) < rho_s, rho_s < -1);


end