Make circular moving object stay within a specific area

Hello, Currently I have successfully implemented an enemy that can moving in a circular motion, however, when I begin the game the enemy goes off to a completely random area of the level. How would I ensure that the enemy stays within a specific area while moving circular? Thank you.

using UnityEngine;
using System.Collections;

public class CircularMovement : MonoBehaviour {

    //timer
    float timeCounter = 0;

    //speed
    public float speed;
    public float width;
    public float height;

	// Use this for initialization
	private void Start () {
        speed = 2;
        width = 2;
        height = 3;

        //start in positon 
        transform.position = new Vector3(53.939f, 1.201f);
        transform.position = transform.position;

    }
	
	// Update is called once per frame
	void Update () {
        timeCounter += Time.deltaTime*speed;

        //directional path
        float x = Mathf.Cos (timeCounter)*width;
        float y = Mathf.Sin (timeCounter)*height;


        transform.position = new Vector2(x, y);
	
	}
}

Hi I tried using the following function and ensuring that I placed the game object correctly but for some reason it still will not work. Any suggestions?

 void OrbitAround()
    {
        transform.RotateAround(Boundary.transform.position, Vector2.right, 3 * Time.deltaTime);
    }