Transmitting phase comparison monopulse estimation using MIMO radar technique for distributed array

3-Dimensional distributed array antenna is considered for radar system [1]. This kind of array antenna can form very narrow beam. A radar system with a distributed array provides high-resolution. However, it has a problem that there are grating-lobes on the beam pattern. To suppress grating-lobes, an effective method is to locate antenna elements nonuniformly [2]. On the other hand, a phase comparison monopulse is widely-used and simple method for direction of arrival (DOA) estimation [3]. This method has a good accuracy and is realized by low calculation amount. There is a requirement for a radar system to use monopulse estimation on 3-dimensional distributed array.