L-band airborne radar application for early detection of stealth aircrafts

When examining the definition and formulations of Radar Cross Section (RCS), it becomes evident that the RCS value is intricately linked to the signal frequency, the geometry of the object, and the properties of the reflective surface material. Due to these underlying factors, the RCS of an aircraft measured in the X-band and L-band will yield distinct values. One of the most crucial parameters concerning a radar's ability to detect a target is the RCS of the desired target. The higher the RCS of a target, the easier it will be detected by the radar; in other words, it will have greater visibility. Stealth aircraft, commonly referred to as "radar-invisible," inherently possess low radar visibility in a specific band. The fundamental reason is that achieving a constant RCS or a low RCS throughout the entire frequency spectrum for an object, such as an aircraft, is not feasible. As mentioned earlier, RCS is fundamentally a function of frequency. Therefore, RCS is typically optimized to be low within the operational frequency band of the radar one seeks to evade. Fighter aircraft, categorized as "Fighters," play a fundamental role in air combat. The nose radars carried by these fighter aircraft operate in the X-band, primarily for the needed detection/tracking precision and resolution, considering size, weight, power, and cooling. Hence, the RCS of a stealth aircraft, aiming to evade radar detection, is designed to be as low as possible in the X-band. In this thesis, the increase in the RCS of a stealth aircraft optimized for the X-band was examined due to the frequency-dependent limited performance of radar-absorbing materials used on the RCS surface as the frequency decreases. Subsequently, an L-band radar, which can be integrated into the wing section of an F-16 fighter aircraft, was designed and the detection range for a stealth fighter aircraft was investigated.