Grating lobe suppression in phased arrays composed of identical or similar subarrays
The grating lobe suppression methods for non-equidistant array antennas composed of identical or similar subarrays are proposed. Subarrays have equidistant rectangular or triangular grid. The grating lobes of an antenna array are reduced due to the irregular arrangement of subarrays. The following methods are considered: relative shift of neighbor subarrays, arranging gaps between subarrays, using different element spacing in different subarrays, rotation of subarrays, and combination of these methods. The methods provide suppression of the grating lobes from −2.6 dB to −11 dB as compared to equidistant arrays while side lobes envelop grows slightly.
Grating Lobe Reduction in a Phased Array of Limited Scanning
Amplitude and phase weighting at the subarray outputs alone causes grating lobes (GLs) in the array factor. A combined approach to disrupt the periodicity in the array is proposed to reduce the GLs. In this approach, three measures are simultaneously used. They are: (1) the optimized amplitude weighting at the subarray ports; (2) using the random subarray; and (3) the random staggering of the rows. The optimization was carried out by using genetic algorithms (GAs). The 24 (along X) times 32 (along Y) phased array was designed to verify the proposed approach. Along Y, the scan range is (-10deg, +10deg) and the subarrays are used. Along X, the scan range is (-45deg, +45deg) without using the subarrays. The comparison was done through array factor. In the whole two dimensional scan space, the simulated results show that the GL is -3.77 dB when using the conventional array, -4.28 dB when using (1) alone, -11 dB when using (2) alone, -14 dB when using (3) alone, -20 dB when using the combined approach proposed in this paper. This approach can be used for a phased array with limited scanning and for the digital beamforming antenna array with adaptive nulling.
Strategies for glass based photonic system integration
There is a clear tendency to integrate more and more opto-electronic and micro-optical components like optical fibers, laser diodes, modulators, isolators, beam-splitting components and micro lenses in also increasingly dense and complex assemblies. The paper will discuss thin glass as a very promising base material for that kind of photonic packaging on interposer and board level including optical interconnection using fibers.