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Figure 5: Impact of the measurement antenna on the DUT AiP antenna elements in a radiating near-field measurement.
assume that there would be some a n t e n n a i s u s e d ,
easy correlation between good AiP depending on the DUT
modules tested in a far-field setup A i P anten na a r ray
with failing AiP modules tested on a geometry, the distance
near-field setup, assuming of course a of each DUT antenna
comprehensive list of performed tests. array element to the
This is a valid thinking, but one needs measurement antenna
to be aware of two important drawbacks will be different. This
on a radiating near-field measurement can have a significant
setup. The first is that the measurement impact on a worst-
antenna is now so close to the AiP c a s e s c e n a r i o a s
DUT antenna array that it will have show in [2,3]. Finally,
an impact on the DUT AiP antenna c a l ib r a t ion i n t h e
elements (antenna detuning) and can radiating near-field is
even result in a standing-wave effect. not trivial. If golden-
This is shown with a simple simulation dev ice cal ibr at ion
in Figure 5 where two patch antennas is used, results are
are simulated with varying distances critically dependent
between them. This effect is also easy on the golden device’s
to see on a real measurement on an AiP p e r for m a n c e , a n d Figure 7: Reactive near-field probing concept for patch and dipole antennas.
module [2,3]. absolute measurements
The second drawback is shown in are not possible. parallel needles to probe the electric or
Figure 6. Because only one measurement magnetic field on the DUT AiP reactive
OTA reactive near-field testing near field. The main advantages are
Another alternative approach for that each element of the DUT AiP
OTA testing with ATE is to measure array is individually measured (power
the DUT AiP antenna array in reactive and phase) and that the probe size is
near field. In this case, a classical very small to minimize the disturbance
measurement antenna cannot be used of ea ch r a d iat i ng element. T h is
because in the reactive near-field range concept is explained in more detail
it would have a dramatic effect on the in [4,5]. Figure 8 shows an example
DUT AiP antenna elements. To measure of a prototype reactive near-field
on the reactive near field, the antenna socket [3]. Note that in the example of
or probing element needs to be very Figure 8, a dual-polarized 2x2 AiP
small. Figure 7 shows one possible array is measured resulting in eight
reactive near-field probing concept individual sig nals. To keep ATE
for OTA ATE that has been patented resources to a minimum (for cost of test
Figure 6: Impact of the single measurement reasons), a solid-state relay switches
antenna position on the distance to the different by Advantest using two very thin each of the antenna/polarization signals
antenna array elements on an AiP DUT.

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