Find Site collection(Root site) by Title using PowerShell

Add-PSSnapin microsoft.sharepoint.powershell -ErrorAction SilentlyContinue
$allsites = Get-SPSite -WebApplication http://portal.kunde.net -Limit All

foreach($site in $allsites)
{
    if($site.Rootweb.Title -contains 'Site Collection Title to search')
    {
        Write-Host $site.Url
    }
}