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Efficient, Low-Loss Combiner Technology for Affordable Transmit and Receive Module Manufacturing
Navy SBIR 2016.1 - Topic N161-031 NAVSEA - Mr. Dean Putnam - [email protected] Opens: January 11, 2016 - Closes: February 17, 2016 N161-031 TITLE: Efficient, Low-Loss Combiner Technology for Affordable Transmit and Receive Module Manufacturing TECHNOLOGY AREA(S): Battlespace, Electronics, Sensors ACQUISITION PROGRAM: PEO IWS 2.0, Air and Missile Defense Radar (AMDR) The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), 22 CFR Parts 120-130, which controls the export and import of defense-related material and services, including export of sensitive technical data, or the Export Administration Regulation (EAR), 15 CFR Parts 730-774, which controls dual use items. Offerors must disclose any proposed use of foreign nationals (FNs), their country(ies) of origin, the type of visa or work permit possessed, and the statement of work (SOW) tasks intended for accomplishment by the FN(s) in accordance with section 5.4.c.(8) of the solicitation. Offerors are advised foreign nationals proposed to perform on this topic may be restricted due to the technical data under US Export Control Laws. OBJECTIVE: Develop a low-loss microwave power combiner technology that is compatible with gallium nitride (GaN) based transmit and receive (T/R) modules. DESCRIPTION: Future Navy radar and electronic warfare (EW) systems will be based on radio frequency (RF) transmit and receive (T/R) module architectures where dozens (perhaps hundreds) of T/R modules are packed tightly behind the array face (Ref. 1). Typically, each individual T/R module contains two or more monolithic microwave integrated circuit (MMIC) high-power amplifiers (HPAs). Within the T/R module, the HPA outputs are combined with a power combiner to supply a required output power, which is determined by system performance and cost trade-offs. Gallium nitride (GaN) on silicon carbide (SiC) MMICs provide the current state-of-the-art for HPA performance and the Navy has invested heavily in GaN to bring the technology to a high level of performance and reliability (Ref. 2). By contrast, far less attention has been given to other key components in the output power path of the T/R module. A number of previous projects have addressed circulator and limiter technology, but the focus of these efforts has typically been to enhance receiver protection, reduce size and weight, or increase bandwidth. Other projects have addressed supporting technologies such as T/R module packaging and thermal management that, though important, do not directly address performance. Within the T/R module, the one remaining component in the transmit chain that has remained largely unexamined is the power combiner. For T/R module designs that combine multiple HPA outputs, the power combiner is integral to the design. Different combiner types have specific features that become part of the trade-space available to the T/R module designer. In general, the complexity and size of the power combiner increases with the number of HPAs that are combined, with the combining efficiency decreasing (Ref. 3). Increasing bandwidth has the same trade-offs. Typically, power combiners used in current T/R modules are direct applications of, or variations on, well-established coupler designs such as the Lange coupler, which has advantageous characteristics, such as wide bandwidth, but is quite large (Ref. 4). These couplers are usually implemented in thick film printed circuit form on ceramic substrates. The technology is mature, reliable, and affordable. The resulting components are easily integrated within the T/R module and are compatible with the automated assembly techniques that are critical to T/R module affordability. Unfortunately, with this technology, the combiner is a relevant source of RF losses and consumes a significant amount of space within the module. The Navy seeks an improved, low-loss, and compact power combining technology at the T/R module assembly level. The current technology is mature but the Navy seeks innovative technology with the potential for real improvement. Combiner efficiency is the key parameter since the entire reason for combining multiple HPAs is to optimize output power. Efficient combining results in a lower heat load on the HPA GaN MMIC, improving reliability. Ideally, the combiner should shield the HPA from load pull effects and present a good output match. However, significant restrictions, arising from performance, reliability, sustainability, and compatibility considerations, complicate the requirements for power combiner technology. First among these is the proposed technology must be compatible with existing GaN-based T/R module technology. This enables transition of the technology to near-future Navy systems such as the Air and Missile Defense Radar (AMDR) in the form of technology updates without requiring fundamental system architecture changes while future designs also benefit. Reliability is also a paramount concern and proposed technologies must have reliable life expectancies comparable to the combiner technology they will replace (a T/R module service life of at least 15 years may be assumed). Finally, affordability being a prime concern, proposed technologies must be compatible with existing automated assembly processes standard to the industry (e.g. pick-and-place assembly) so that it may be easily inserted into the manufacturing process. As a guideline, a 50% increase in combiner cost over that of current thick film on ceramic technology is acceptable. This topic serves to increase mission capability by enhancing basic sensor (radar and EW system) performance such as detection range. A secondary benefit is increased system efficiency, which translates into reduced cooling load and, as a result, decreased operating cost. The Navy is making a huge investment in T/R module based phased array systems that incorporate hundreds of modules in each array face. Extracting the maximum power possible from each T/R module optimizes system performance and produces the greatest return on investment in the system. This topic seeks to optimize power output without requiring any changes to system architecture, power supply, or the form factor of individual T/R modules. Therefore, this topic serves to increase capability at the lowest possible cost. PHASE I: The company will develop a concept for innovative, low-loss, and compact power combining technology compatible with GaN HPA based T/R modules that meets the requirements stated in the topic description. The company will demonstrate the feasibility of their concept in meeting Navy needs and will establish that the concept can be feasibly produced. Sample testing, modelling, simulation, and analysis will establish feasibility. The Phase I Option, if awarded, would include the initial layout and capabilities description to build prototypes in Phase II. PHASE II: Based on the results of Phase I and the Phase II Statement of Work (SOW), the company will develop prototype power combiners and the associated techniques for integrating the combiners with GaN HPAs consistent with current T/R module designs and assembly practices as described in the description. The prototypes will be evaluated to determine their capability in meeting the performance goals defined in the Phase II SOW and the Navy requirements for improved power combiners for T/R modules. Performance will be demonstrated by the company through prototype testing over the required range of parameters including numerous thermal cycles. Testing may be augmented by modeling and analytical methods. Evaluation results will be used to refine the prototype into an initial design that will meet Navy requirements. The prototype will be delivered at the end of the Phase II. An automated assembly plan will be required to demonstrate compatibility with automated T/R module manufacturing practices. The company will prepare a Phase III development plan to transition the technology for commercial use to supply Navy needs. PHASE III DUAL USE APPLICATIONS: The company will be expected to produce its combiner technology and support the processes required for its successful use in future Navy radar and EW systems. The company will develop and fully document the processes required to integrate the technology for use by industry according to the Phase III development plan. The technology will be evaluated to determine its effectiveness in full-rate production of T/R Modules incorporating GaN MMIC HPAs. The US domestic RF amplifier business supplies commercial as well as military markets. Advances in compact transmitter technology, though first implemented in military systems, eventually transitions to commercial product lines. Since this topic seeks to develop a fundamental product for power combining at the MMIC integration level and not a specific military application, the potential for commercial application is significant. The potential commercial market is essentially unlimited, should the technology prove cost competitive. REFERENCES: 1. Kopp, Bruce A., et al. "Transmit/Receive Modules." IEEE Trans. Microwave Theory and Techniques 50 March 2002: pp. 827-834. 2. Campbell, Charles, et al. "GaN Takes the Lead." IEEE Microwave Magazine 13 Sept./Oct. 2012: pp. 44-53. 3. Katehi, Linda, et al. "3-D Integration of RF Circuits Using Si Micromachining." IEEE Microwave Magazine 2 March 2001: pp. 30-39. 4. Marsh, S. P. "MMIC Power Splitting and Combining Techniques." IEE Tutorial Colloquium on Design of RFIC�s and MMIC�s, Nov. 26 1997: pp. 6/1-6/7. KEYWORDS: Power combiner; high-power amplifiers; GaN MMIC; Lange coupler; pick-and-place assembly; T/R module TPOC-1: Larry Dressman Phone: Email: [email protected] TPOC-2: Bryan Mitsdarffer Phone: 812-854-5264 Email: [email protected] Questions may also be submitted through DoD SBIR/STTR SITIS website.
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