| Description: | A differential amplifier has been designed and taped out in Oct. 2006 and was received back at Astron last month. The chip consists of a low noise differential negative feedback amplifier, which is the main building block of the EMBRACE beamformer chip. Testing has been performed with good results. It showed a stable amplifier, with a differential gain of 28 dB between 100MHz and 1500 MHz without any decoupling! The figure shows also the measured and simulated differential gain of the amplifier. One can see that the measured results resemble quite well with the typical simulation results (including layout parasitics). It also shows that the measurement lies within the corner deviations of the used process (0.25um SiGe BiCMOS). This tells us that we can rely on the simulated results, which gives confidence in the next iteration of the beamformer chip. 16 beamformer chips will be located in an EMBRACE tile, where it is able to control the direction of the beam by altering the phase of 64 RF signals coming from the antennas. The beamformer chip will have 4 differential inputs, and two differential outputs for two independent analog beams. At this moment the EMBRACE team is working hard to complete the last layout parts and verifications of the 4 channel differential beamformer chip.
Klaas Visser, Erik vd Wal, Dion Kant, Mark Ruiter
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