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Testing AiP modules in high-volume production for

5G applications

By Jose Moreira [Advantest]
T his article is a follow up a 0.4mm pitch for the BGA array on the that AiP modules come in a multitude

bottom of the PCB. The objective was not
to a r t icle [1] where we
of package types [3]. We chose this one
described different options
for high-volume over the air to create a 5G-compliant antenna array, because it was the simplest to design
and manufacture.
but just a demonstration vehicle. Note
(OTA) testing of antenna in package
(AiP) modules with automated test
equipment (ATE). We also presented
a high-level compar ison of their
advantages and disadvantages. In
this follow-up article we will present
measurement results for two of the
presented OTA testing approaches:
far-field and radiating near-field OTA.
But before we go to the measurement
results, we need to first define an AiP
device under test (DUT) that can be
used as a DUT for the measurements.

Creating an AiP evaluation vehicle
To properly evaluate an ATE OTA
measurement setup, it is critical to use
an AiP module. Using, for example, Figure 1: Simple antenna in package module demonstration vehicle for OTA measurements.
a reference antenna instead of an AiP
DUT (e.g., a reference horn antenna)
would not take into account all the
components that are specific to an
ATE implementation like the DUT test
fixture printed circuit board (PCB) or
the DUT socket. Using a commercial
AiP module is also not currently a
feasible option because there are
very few commercially-available AiP
modules and there would always be
intellectual property (IP) restrictions
on using them to publicly show OTA
measurement results.
Because of the reasons cited above,
we decided to create the simple AiP
module shown in Figure 1. The module
was manufactured in a multilayer PCB
with a Rogers 4350B top layer and a ball
grid array (BGA) on the bottom. The
antenna array comprises a 2 by 2 array of
dual polarized patch antennas [2]. They
are a microstrip feed with two quarter-
wavelength transformers for impedance
matching. This antenna design is narrow
band, and it was tuned for 28GHz, but
can support our measurement modulation
range, which will be 100MHz. We used Figure 2: Socket lid impact in the AiP module antenna array beam: a) (top) without a lid, and b) (bottom) with a lid.

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