Downgrade Angular 6 directive to Angular 1.7

Question

I would like to downgrade an angular 6 directive defined something like this

@Directive({
  selector: '[ad-host]',
})
export class AdDirective {
  constructor(public viewContainerRef: ViewContainerRef) { }
}

to angular 1.7 but angular https://angular.io/api/upgrade/static module contains downgradeComponent only.

any suggestion how to do so.

the main problem that I am trying to solve is to achieve parent-child communication for children rendered using by the parent and as per https://blog.angular-university.io/angular-ng-content/ blog I can achieve by having inputRef directive.