DSP-17-08-005/A/JD

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1. INTRODUCTION

The patent pending CMM200 Massive MIMO Modular Passive Panel is the preferred testbed for

Massive MIMO research, allowing the radio researcher ease and flexibility in assembling an array

of variable size and shape which always has constant array spacing for minimization of grating

lobes.

The modules attach to each other and to ground plane extensions with a proprietary fastening

design that enables quick assembly without threaded fasteners. When attached, a module-module

or module-extension connection has excellent ground plane continuity due to a conductive

elastomeric gasket around the periphery that ensures optimal field pattern from each element.

Each module has 16 patch antenna elements, each having a dual polarization with very high cross

polarization isolation and low mutual coupling between adjacent elements.

Massive MIMO reciprocity calibration is accomplished easily with the modules, because each

module has a network of couplers that meanders through the antenna PCB, coupling energy off of

each of the 2x16 radiating elements, and connecting to a common RF calibration (CAL) port. There

is also an additional port in this calibration network for daisy chaining the calibration line to other

modules (CAL_DAISY) which can permit a single connection to the reference radio used for

calibration.

The radiating elements are high-efficiency patch antennas which are soldered to the antenna PCB

for the highest reliability and performance. These exhibit good return loss and field pattern over

a broad bandwidth, enabling freedom of choice in the research frequency used.

The modules have an integrated radome made of high-impact UV stabilized plastic. The radome

is sealed to the housing with an O-ring which supports IP55 immersion rating for outdoor

operation.

Each module has on the back side a set of 34 SMA connectors for the 32 antenna ports and two

reciprocity calibration ports.

The modules can be delivered pre-assembled with cables for

increased ease of use.