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Introduction
Published in Hema Singh, Avinash Singh, Low Radar Cross Section HIS-Based Phased Array, 2020
The design of stealth weapon systems such as combat aircraft or missiles requires low radar cross section (RCS) signatures. It involves the reduction of infrared, optical and other electromagnetic signatures of such aerospace platforms, warships and vehicles in hostile environments. One of the countermeasures to eliminate or reduce this threat is to minimize the RCS and thereby diminish the detectability of the target.
Radar Fundamentals
Published in Habibur Rahman, Fundamental Principles of Radar, 2019
Radar signatures relate to the determination of target physical characteristics, including radar cross section (RCS), Doppler spectrum, and imaging. RCS is basically the target cross section as seen by the radar. This is a quantitative measure of the ratio of the power density in the vector signal scattered in the direction of the receiver to the power density of the radar signal incident upon the target. The returned energy, hence the RCS, is dependent on many parameters such as wavelength of the transmitted electromagnetic energy, target geometry, orientation, polarization combination, and reflectivity. Thus, in most cases of practical concern, RCS may vary over rather wide limits because of the changes in any of these parameters. RCS is usually extracted from the knowledge, a priori, of the radar design parameters, and by measuring the strength of the received echo and the target range.
Communication Systems
Published in Arun G. Phadke, Handbook of Electrical Engineering Calculations, 2018
Aircraft are complex targets at microwave frequencies because their dimensions are always a large number of wavelengths. Strong echoes can be obtained when part of the aircraft acts as a corner reflector (two surfaces at right angles). These reflections may correspond to an RCS of 10,000 m2. An RCS of 2m2 represents the minimum expected reflecting area for a large aircraft and the typical RCS of a single-engine general aviation aircraft. In the military environment, stealth technology is aimed specifically to reduce the RCS of an aircraft to make it more difficult for the radar to detect.
Structural–electrical coupling optimisation for radiating and scattering performances of active phased array antenna
Published in International Journal of Electronics, 2018
Congsi Wang, Yan Wang, Zhihai Wang, Meng Wang, Shuai Yuan, Weifeng Wang
The active phased array antenna (APAA), a kind of array antenna, has been widely used in radar and communication systems because of its high reliability, multifunction and good ability to detect, track and stealth. The analysis and calculation of the antenna’s radiating and scattering fields have always been the research focus because antenna’s detection range and stealth performance depend respectively and heavily on them (Ahmed, Khan, & Rehman, 2016; Wang et al., 2017). Radar cross section (RCS) is a physical quantity representing the scattering strength of the target. As a radiating element, the antenna is more complicated in scattering mechanism. Moreover, the RCS is reduced usually at the expense of the radiating performance. Therefore, it is a knotty problem for researchers to balance the performance of the radiating and scattering when the RCS is reduced.
Mutual coupling and RCS reduction of MIMO dielectric resonator antenna for S-band applications
Published in Waves in Random and Complex Media, 2022
Manoj Kumar Maurya, Ajay Kumar Dwivedi, Nagesh Kallollu Narayaswamy, Ashish Pandey, Vinay Kumar, Anand Sharma
Different researchers have proposed various types of CP DR-based MIMO antennas. Das et al. presented a circular polarized DR-based MIMO antenna within 5.27–5.9 GHz. The authors used a perturbed circular aperture to create the CP waves (5.6–5.9 GHz). The isolation between the ports has been improved by 15 dB with the assistance of defected ground structure (DGS) and the polarization diversity concept [4]. Singhwal et al. proposed a two-port ring-shaped ceramic antenna fed by an L-shaped printed line. It can support frequency ranges from 3.15 to 3.9 GHz and CP waves from 3.26 to 3.45 GHz. A triangular slot on the ground plane improves the isolation by 20 dB [5]. Varshney et al. proposed two adjacent placed semi-cylindrical ceramics fed by the conformal strips. Due to adjacent placing CP waves are created within 7.72–8.04 GHz and 15 dB isolation [6]. Dual-port ring-shaped ceramic antenna fed by moon-shaped aperture is proposed by Bharti and his colleagues. This antenna operates in the frequency range 2.4–3.88 GHz and CP waves 2.44–2.64 GHz. Orthogonal placing improves the isolation level by 20 dB [7]. Hu et al. proposed a dual-port cross-shaped aperture coupled rectangular DRA. This radiator works from 2.38 to 2.52 GHz with an improved isolation level 31 dB and CP waves are achieved from 2.39 to 2.51 GHz [8]. Chauhan et al. proposed two different DR-based MIMO antennas with wide impedance bandwidth. In the first design, spiral-shaped ceramic is used, which supports 8–15.1 GHz [9]. In the second one, three half cylindrical-shaped DRA is used, which supports 8.7–11.6 GHz [10]. In various wireless applications (particularly in defense applications), the RADAR cross-section (RCS) is an essential factor. Some of the researchers have focused on the reduction of RCS. Different techniques have been used for this purpose, such as resistive loads [11], ferrite material-based substrate [12], and EM waves absorbing materials [13]. Also, frequency-selective surfaces are widely used to reduce the RCS value. Thummaluru et al. proposed a two-port printed antenna and used the frequency-selective surface (FSS) structure to reduce the value of RCS by an amount of 20 dBsm [14]. As mentioned above, it is observed from the literature that there is no work associated with RCS reduction for the DR-based MIMO antenna.