What is the name of the combined antenna unit commonly used in modern aircraft?

The combined antenna unit commonly used in modern aircraft is referred to as a loop-and-sense antenna. This type of antenna is specifically designed to improve the performance of communication and navigation systems. The loop-and-sense configuration allows it to receive and transmit a wide range of frequencies, making it versatile for various avionics applications.

One of the key reasons for its prevalence in aircraft is its ability to provide reliable performance in various conditions and environments, where factors such as interference and antenna placement can significantly impact effectiveness. The loop-and-sense antenna's design enhances its reception capabilities, especially for VHF radio communications and other navigational tasks, thereby contributing to overall safety and efficiency in aviation systems.

Other types of antennas, like the cardinal, Yagi, and biconical antennas, serve more specialized applications and are less commonly employed as integrated units in aircraft avionics. For instance, Yagi antennas are typically used in highly directional applications, and biconical antennas are usually used for broadband applications, while cardinal antennas are more suited for specific types of communication rather than the dual functions that a loop-and-sense antenna can provide in a compact form factor.