You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: PL_Hata.m
    path of file: ./repos/MIMO_OFDM/第1章 无线信道：传播和衰落/Okumura&Hata模型
    
    the code of the file until where you have to start completion: function PL=PL_Hata(fc,d,htx,hrx,Etype)

    
function PL=PL_Hata(fc,d,htx,hrx,Etype)
% Hata Model
% Input
%       fc    : carrier frequency[Hz]
%       d     : between base station and mobile station[m]
%       htx   : height of transmitter[m]
%       hrx   : height of receiver[m]
%       Etype : Environment Type('urban','suburban','open')
% output
%       PL    : path loss[dB]
if nargin<5, Etype = 'URBAN'; end