A New Method for Linear Antenna Array Design
Yang WANG1, Jinming DONG2,
1 RF Lab (Hong Kong) Limited, Room 414,
4/F., International Plaza, 20 Sheung Yuet Road, Kowloon Bay, Kowloon,
Hong Kong,China
2 Electronic Engineering Department, Beihang
University, 37 Xueyuan Road, Beijing 100083, China
Email: yang_t_wang@hotmail.com.
The inherent relation between the linear antenna array and the finite
impulse response filter of digital signal processing is revealed and the
least square linear-phase finite impulse response filter design method
is introduced for the linear antenna array to obtain a similar main lobe
width of uniform linear antenna array but much lower sidelobe level.
Introduction: The linear antenna array (LAA) is a widely used for
airborne target detection. The main efforts are focusing on reducing its
sidelobe level while trying to keep the main lobe being narrow. In
addition, the phase control concept was introduced to allow the LAA
scanning, and the uniform linear antenna array (ULAA) is always the
research platform [1]. From the LAA phase point of view, the ULAA is
just the finite impulse response (FIR) filter of digital signal
processing (DSP) [2] with the rectangle window function (RWF).
Beside RWF, there are many high-performance ones available for LAA
design. However, the availability of low sidelobe level is at the price
of the wider main lobe for the window functions based LLA. A more
effective FIR filter design method called least-square linear-phase
design can be employed for the LLA design to balance the tradeoff
between the low sidelobe level and narrow main lobe.
The relation between LLA and FIR Filer: The LAA can be shown as
Fig.1. The distance d between the adjacent elements is \(\lambda/2\),
where λ is the wavelength; and the incident angle is\(\theta\). So, the phase difference between the adjacent elements is
kdcos\(\theta\), where k is 2\(\pi\)/\(\lambda\).