How many Janus pairs exist in a four beam Janus array?

In a four beam Janus array, the configuration is structured such that each beam can interact with another beam to form pairs, known as Janus pairs. A Janus pair consists of two beams that work in coordination to achieve specific radar functions.

In a four beam configuration, you can determine the number of possible Janus pairs by considering the different pairings you can have among the four beams. With four distinct beams, each beam can pair with another, resulting in a combination where you can form pairs from the available beams.

Mathematically, this can be viewed as a combinatorial problem, where you are interested in selecting 2 beams out of the 4 available. The formula for combinations is given by C(n, k) = n! / (k!(n - k)!), where n is the total number of items and k is the number of items to choose.

Applying this to the case of the four beam Janus array, where n is 4 and k is 2, we can calculate the number of pairs:

C(4, 2) = 4! / (2!(4 - 2)!) = (4 × 3) / (2 × 1) = 6.