The EMPF in a partnership with ONR, NAVAIR and Rockwell Collins, has undertaken the Link 16 PAI Affordability Program to develop a highly manufacturable Power Amplifier Interface (PAI) unit for the Link-16 Multifunctional Information Distribution System Low Volume Terminal (MIDS LVT1, Figure1-3) currently employed on E-2C, F/A-18 and F-16 platforms (Figure 1-1).

The purpose of this project is to re-layout and re-package the 200 Watt PAI portion of the terminal to reduce cost, size and position the equipment for inclusion in smaller size terminals. This will be accomplished through the use of industry state-of-the-art technologies in circuit boards, semiconductor packaging, MMIC devices, and heat-transfer and by incorporating new technologies, including Wide Band Gap (WBG) devices, that enable low/no tune strategies to enhance the producibility and significantly reduce the cost of the PAI.

The goals of this program include a 40%reduction in cost of the PAI for the LVT1, as well as to achieve a significant reduction (20% volume and 15% weight)of the physical size enabling the potential utilization in size limited applications such as missile systems, patrol boats, armored vehicles and rotary platforms. Additionally, all U. S. Government equipment programs will benefit from the semiconductor, packaging, and manufacturing technology being advanced and transferred across industry. Specifically, NAVY Communications, Electronic Warfare, and Radar programs desiring the use of WBG semiconductors will benefit by an earlier implementation of this technology.

The EMPF will promulgate industry standardization of modular and WBG packaging methods based on lessons learned during the execution of the program. This effort will include the evaluation of various methodologies to mitigate the thermal challenges that accompany WBG devices. This article will discuss the opportunities for redesign and a proposed new design concept.

In the conceptual redesign of the LVT1 PAI, emphasis was placed on partitioning to modules that performed a specific electrical function that would be portable from location to location within this design and/or applicable to other designs. Additionally, electrical functions that could be tested or tuned and known assembly time and material cost drivers were also considered.


The first proposal is to combine the Transmit and Receive functions into one printed wiring assembly, with interconnection between the two accomplished by using thru-holes or transitions within the PWB. Increasing the dielectric constant of the substrate would allow this AIU board size to be reduced relative to the existing design. The receive function would include two identical modules containing one low noise amplifier, two buffer amplifiers, bias circuitry, splitters and an output antenna select switch, all mounted to the backside of the new AIU board. The benefits of this redesign include reduced testing, a simplified chassis design, reduced assembly time and a simplification in terms of rework.

The control function of the PAI could be accomplished by creating multi chip modules (MCM) for each of the three main sub-functions of the current design. These MCM's would then be mounted in appropriate locations to take advantage of existing circuit board laminate structure. The control Power Amplifier function would be assigned to one MCM and combined with the main PA section of the PAI.

Similarly, a PIN diode driver MCM would be mounted on the AIU combined board. The remaining front end control MCM would be housed on a "mother board" that will interconnect the AIU, power supply, and PA sections. Within the power supply section of the LVT1 PAI, the use of a commercially available power supply module produced by VICOR® was a driving factor in the conceptual redesign.The use of two of these modules will provide the necessary power.

The important areas regarding the redesign of the PA section of the LVT1 PAI were:

• Developing and implementing modules will help reduce overall material costs as modules may be used for other programs.
• Modules may be tested and tunable at a lower assembly level and be easier to rework. Thermal management may be easier in a module.
• Finally, consideration of alternative Power Amplifier technologies, such as LDMOS or Wide Band Gap materials can result in higher RF power, fewer output stages and fewer support components.

All modules would be housed in a single machined metal chassis, providing significant weight reduction.

Upon completion of this project, the U. S. Navy will have anew, miniaturized and affordable PAI, validated through independent testing by Rockwell Collins and the EMPF. The new PAI will be qualified for use in the currently field¬ed MIDS LVT1 terminals. Additionally, this PAI will be sized positioned for new smaller terminals which will better fit platforms that have less space available, such as missile systems, UCAV, patrol boats, armored vehicles, and rotary platforms.