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an elastomer socket because we needed
to support 28GHz signaling. The DUT
test fixture is a very simple mmWave
design with the signals from the
Anokiwave evaluation board connected
to the DUT AiP via microstrip traces.
We also implemented some auxiliary
test and calibration structures. The
Anokiwave evaluation board resides
on a garage space below the DUT test
fixture. It is powered by the ATE power
supplies, and it is programmed with ATE
digital channels using a serial peripheral
interface (SPI). Figure 5 shows the
ATE system configured for far-field and
radiating near-field OTA measurements.
All the measurements presented in the
next sections were performed using an
Figure 3: Block diagram of the used ATE OTA measurement setup. Advantest V93000 WaveScale mmWave

In order to obtain constr uctive in Figure 3, we can fully emulate the ATE system.
i nt e r fe re nce of r a d iat ion i n t he OTA testing of an AiP module. In the Before we go ahead with the OTA
direction normal to the antenna array ATE system used for the presented measu rements of this evaluation
plane – while feeding all four co- measurements, only two ATE mmWave AiP module, it is necessary to have
polarized patches – adjacent patches measurement channels were available. some reference numbers for the far-
must be fed in-phase and patches Therefore, we used a solid-state switch field distance from the antenna array.
on the opposite side must be fed to switch between polarizations. Figure 6 shows the AiP anten na
with a 180 degree phase difference. Figure 4 shows the DUT test fixture array dimensions. It also shows a
By selecting the appropriate phase (or load board) with the far-field socket computation of the far-field distance
difference, it is then possible to move installed, but without a DUT. For the using the Fraunhofer distance equation
the beam direction as expected for electrical side of the AiP module we used [4]. The computed far-field starting
an AiP phased-array antenna. One distance is 32mm for this case.
critical point on OTA testing of AiP
modules with ATE is that a socket Results with a far-field OTA
must be used. The challenge is that measurement setup
the socket lid will have an impact on In the far-field setup (Figure 5a), the
the antenna array beam as shown in measurement antenna is a dual-polarized
Figure 2. But in an ATE environment, horn antenna (Ainfo LB-SJ-180400) that
a DUT socket is always a must. One is at a 10cm distance from the DUT AiP.
can try to minimize the impact of the So it is clearly in the far-field zone (see
socket by proper design and material Figure 6). The measurement antenna
selection (especially the lid), but at the Figure 4: DUT test fixture. gain is known. Because the measurement
same time there are other conflicting
r e q u i r e m e n t s i n a h ig h -vol u m e
production test cell. These include,
for example, suppor ting hot and
cold testing, as well as guaranteeing
a proper electrical contact into the
electrical side of the socket even in the
presence of a small package warpage.
The missing point to achieve a
complete AiP module emulation is the
active part—that is, the silicon die,
which is part of any AiP module. To
emulate that part, we used an external
evaluation board (Anokiwave 0151-
DK). This board provides four dual-
polarized mmWave channels with
independent phase and gain control
of each channel. With this complete
setup shown in the high-level diagram
Figure 5: ATE measurement setup showing a) (left) the far-field setup, and b) (right) radiating near-field setup.

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