A General Analytical Arrangement for Large-Spacing Planar Scanning Array Grating Lobe Suppression Based on Energy Homogenization Theory

This communication introduces a general analytical method for suppressing the grating lobes (GLs) of planar scanning arrays with spacing exceeding half a wavelength from an array configuration perspective. First, the positions of GLs are analyzed, followed to derive an analytical relationship between the positions of these GLs and the spacings of the element. On this basis, a general array arrangement expression with arbitrary-order GL suppression capabilities is derived. With this arrangement approach, an analytical method for suppressing GLs is proposed without limiting the spacing, bandwidth, and element pattern. Afterward, a series of numerical results are presented, and a prototype with a relative bandwidth of 22.3% is fabricated and measured to validate the proposed method. The measured results show that the prototype array with spacing at least greater than one wavelength can steer its main lobe from -50 degrees to 50 degrees both in the E- and H-planes and maintain the sidelobe levels (SLLs) less than -6.2 and -5.1 dB and scan loss less than 5.4 dB. The SLLs improve further with the exponential increase in the number of elements.