backup mysql database

With the function below I backup a copy of my database, but something very curious happens to me: If I do it on the local server, it responds:

INSERT INTO calendar (guest) VALUES (" muà ± oz Gómez ");

On the remote server:

INSERT INTO calendar (guest) VALUES (" muñoz Gómez ");

same structure BD, same version php 7.0, ????

I DO NOT UNDERSTAND !!!

Thanks

function backupDatabaseTables($dbHost,$dbUsername,$dbPassword,$dbName,$tables = '*'){
//connect & select the database
$db = new mysqli($dbHost, $dbUsername, $dbPassword, $dbName); 

//get all of the tables
if($tables == '*'){
    $tables = array();
    $result = $db->query("SHOW TABLES");
    while($row = $result->fetch_row()){
        $tables[] = $row[0];
    }
}else{
    $tables = is_array($tables)?$tables:explode(',',$tables);
}

//loop through the tables
foreach($tables as $table){
    $result = $db->query("SELECT * FROM $table");
    $numColumns = $result->field_count;

    $return .= "DROP TABLE IF EXISTS $table;";
        $campos2=mysqli_query($db, "SELECT COLUMN_NAME as columna FROM INFORMATION_SCHEMA.COLUMNS WHERE table_name = '$table' and table_schema = 'trinid_alquiler' " );
$a=0;             
while ($campos= mysqli_fetch_assoc($campos2)){ 
    if ($a < ($numColumns-1))                         
    {$retur.=$campos['columna'].",";}else{$retur.=$campos['columna'];}
    $a++;
 }
    $result2 = $db->query("SHOW CREATE TABLE $table");
    $row2 = $result2->fetch_row();

    $return .= "\n\n".$row2[1].";\n\n";

    for($i = 0; $i < $numColumns; $i++){
        while($row = $result->fetch_row()){
            $return .= "INSERT INTO $table";
        $return .=  "(".$retur.")";

        $return.=" VALUES(";
            for($j=0; $j < $numColumns; $j++){
                //$row[$j] = addslashes($row[$j]);

                 if (isset($row[$j]) and ($row[$j]!=="")){ $return .= '"'.$row[$j].'"' ; }
                else if(is_null($row[$j] )) { $return .= 'NULL';       }
                else { $return .= '""'; }
                if ($j < ($numColumns-1)) { $return.= ','; }
            }
            $return .= ");\n";
        }$retur="";
    }

    $return .= "\n\n\n";
}