*Question E9H09:
What type of radiation pattern is created by a single-turn, terminated loop such as a pennant antenna?*  

*Correct Answer is  A: Cardioid*  

### AI Response: (may contain errors)  

A single-turn, terminated loop antenna, like a pennant antenna, creates a cardioid radiation pattern. Here's why:

1. **Why the correct answer is correct (Cardioid):**
   - A cardioid pattern is characterized by a heart-shaped radiation pattern with a single main lobe and a null in the opposite direction. This pattern is typical for a terminated loop antenna because the termination causes the antenna to have a directional pattern with a strong front-to-back ratio. The termination absorbs energy in one direction, creating a null, while the other direction has maximum radiation.

2. **Why the other choices are incorrect:**
   - **Bidirectional:** A bidirectional pattern has two main lobes in opposite directions, which is typical for a non-terminated loop antenna. Since the pennant antenna is terminated, it does not exhibit this pattern.
   - **Omnidirectional:** An omnidirectional pattern radiates equally in all directions, like a circle in the horizontal plane. This is not the case for a pennant antenna, which is directional due to its termination.
   - **Hyperbolic:** A hyperbolic pattern is not a standard term used to describe antenna radiation patterns. It does not apply to the pennant antenna.

In summary, the termination of the loop in a pennant antenna creates a cardioid pattern, making it highly directional with a strong front-to-back ratio, which is why the correct answer is "Cardioid."