Решение 1 с функцией небольшого пакета
<?php
function chr_utf8($n,$f='C*'){
return $n<(1<<7)?chr($n):($n<1<<11?pack($f,192|$n>>6,1<<7|191&$n):
($n<(1<<16)?pack($f,224|$n>>12,1<<7|63&$n>>6,1<<7|63&$n):
($n<(1<<20|1<<16)?pack($f,240|$n>>18,1<<7|63&$n>>12,1<<7|63&$n>>6,1<<7|63&$n):'')));
}
echo chr_utf8(9405).chr_utf8(9402).chr_utf8(9409).chr_utf8(9409).chr_utf8(9412);
//Output ⒽⒺⓁⓁⓄ
Проверьте это в https://eval.in/748062…
Решение 2 с json_decode
<?php
$utf8_char='["';
for($number=0;$number<55296;$number++)
$utf8_char.='\u'.substr('000'.strtoupper(dechex($number)),-4).'","';
$utf8_char=json_decode(substr($utf8_char,0,-2).']');
echo $utf8_char[9405].$utf8_char[9402].$utf8_char[9409].$utf8_char[9409].$utf8_char[9412];
//Output ⒽⒺⓁⓁⓄ