将变量放在require函数中

I'm trying to require a php view dynamically. So that it print a pdf using phpwkhtmltopdf.

First I send the name of the viewer page from my handler page by using a button:

<form action="print.php" method="get">
 <button name="printit" type="submit" value="m_dpgmi1.php">print</button>
</form> 

Then I catch it in the page where I've the phpwkhtmltopdf function:

<?php
require '../vendor/autoload.php';

$template = $_GET['printit'];    

use mikehaertl\wkhtmlto\Pdf;

ob_start();

require "'$template'";
$content = ob_get_clean();

// You can pass a filename, a HTML string, an URL or an options array to the constructor
$pdf = new Pdf($content);

$pdf -> setOptions(['orientation' => 'Landscape']);
$pdf->binary = 'C:\Program Files\wkhtmltopdf\bin\wkhtmltopdf.exe';
$pdf->send();
?>

Unfortunately I get an error:
Warning: require('m_dpgmi1.php'): failed to open stream: No such file or directory

It looks right require('m_dpgmi1.php'), except for the braces. Is there a way to place a variable value as an require argument?