This is a standard thing in beamforming especially Mvdr the algorithms produce weights and if I wanted to transmit with the weights I need true time delay not phase shifters.
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2$\begingroup$ Please clarify your specific problem or provide additional details to highlight exactly what you need. As it's currently written, it's hard to tell exactly what you're asking. $\endgroup$– Community BotCommented Mar 17 at 10:24
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$\begingroup$ Besides clearing up the question, specifically why do you claim that you need TTD to transmit? You've made no mention about bandwidths which is the main deciding factor in choosing phase or TTD steering. $\endgroup$– EnvidiaCommented Mar 17 at 16:14
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The amplitude change is useful even with TTD for reducing spatial sidelobes equivalent to windowing used in FFT and FIR filters. The TTD instead of phase shifters eliminates a spatial frequency dependence that we would otherwise get with phase shifters that produce a constant phase over frequency (TTD in contrast produce a phase that changes linearly with frequency).
Given antennas at different spatial locations, the signal received at each antenna will be the same signal with a different time delay based on the spatial direction from the source, independent of the frequency of the source. Similarly if we changed the signal applied to the antennas with a time delay, it would change the direction of propagation. A time delay is a frequency varying phase shift (the Fourier Transform of $x(t-\tau)$ is $X(\omega)e^{-j\omega \tau}$, thus the phase in radians as $-\omega \tau$ is dependent on both frequency $\omega$ and time delay $\tau$), whereas a phase shifter applies the same phase at all frequencies. For narrow band signals we can use a phase shifter, but since the phase does not change with frequency, the result for a beamformer would be a frequency varying direction. For wireless communications this would result in a passband slope resulting in (correctable) inter-symbol interference. A true time delay will result in beamforming that is independent of frequency and dependent on space alone which is generally what we would want for a beamforming application.
