Let the length of the field be $l$ meters. Since the width is half as wide as the length, the width is $l/2$ meters.
The perimeter of the field is the sum of all sides, which is $l + l/2 + l + l/2 = 3l$ meters.
We know that the perimeter is 54 meters, so $3l = 54$.
Dividing both sides of the equation by 3, we find that $l = 18$.
The area of a rectangle is the product of its length and width, so the area of the field is $18 \times (18/2) = 18 \times 9 = \boxed{162}$ square meters.
The answer is: 162
Below is a math problem. Provide a detailed, step-by-step solution.

### Problem:
A rectangular field is half as wide as it is long, and it is completely enclosed by 54 meters of fencing. What is the number of square meters in the area of the field?

### Answer:
