A Flexible Integrated Photonic True Time Delay Phaser for Phased Array Antennas

Abstract

Abstract-An integrated photonic True Time Delay phaser for phased array, based on an innovative technology, is here presented. The module versatility is showed by presenting more driving strategies matching different antenna features. The phaser insertion loss, the fluctuations of the excitation coefficients corresponding to the various driving configurations and the statistical modeling of the realization defects are also discussed.

The Design of an Optical Time Steered Antenna Based on a New Integrated True Time Delay Unit

“…Points I and IV have already been discussed in [25]. Here we summarize the design formulas related to the maximum time delay τ max and spend some words regarding the time delay quantization.…”

“…, (2 M − 1)τ e , multiples of an elementary one, say τ e , giving a maximum achievable time delay τ max = (2 M − 1)τ e . As discussed in [25], for a linear array of N elements/subarrays, with uniform spacing d, radiating a beam pointing at an angle θ with respect to the normal to the array, the value for τ max is related to the desired maximum beam pointing angle θ max and to the radiating system aperture A = (N − 1)d by the equation:…”

“…Regarding the number M of quantization bits, it must be noted that a high value for M , although reducing the time delay quantization error, also increases hardware complexity and losses. In fact, larger quantization levels require larger numbers of delay stages, thus increasing the total losses and hardware complexity of each time shifter, as discussed in [25,26].…”

“…Two simple configurations (3 and 5 BITS) based on mono-directional driving have been reported in [25], while here we will consider a 3 BEAM strategy and a 5 BITS configuration, the latter based on a bidirectional driving: 1) 3 BEAM -6 elements -Contiguous outputs; 2) 5 BITS -4 elements (bidirectional driving) -Contiguous outputs.…”

“…The first is to show the potentialities of the integrated optical TTD unit presented in [24], called TTDU later on. It is an integrated device, based on the SDL scheme, compact and very flexible, whose performance compared to those of competitor SDL's are summarized in [25].…”