Multifunction Modules Save Integration Time

Multifunction Modules Save Integration Time

By combining components within a common housing, RF/microwave engineers are performing some of the integration needed to add high-frequency functionality to commercial and military systems.

The AIR modules incorporate all matching and supporting circuitry, along with a transceiver IC, to simplify addition of wireless capability to a product.>
Multifunction modules save space, time, and engineering effort for system integrators. Rather than trying to match a local oscillator (LO) to mixers and filters in a frequency converter, for example, or switches and filters in a signal-routing subsystem, such nuances as reflections and impedance mismatches can be minimized when related functions are supplied as integrated units. In many ways, multifunction modules represent the fruits of component suppliers that have taken on a small portion of system engineering. Not all RF/microwave components suppliers also offer multifunction modules; those that do devote considerable resources in design, manufacturing, and test to getting the job done right.

Multifunction assemblies, which were once known as "supercomponents," may be as basic as a switch and a pair of filters within a common housing. The model PSFB7-0618-11-11 from Paciwave, for example, is a switched filter bank that packs a pair of high-speed (50-ns switching speed) single-pole, six-throw (SP6T) switches and six filter channels with TTL control into a compact housing. It measures 4.000 x 3.920 x 0.600 in. with SMA connectors and control and power pins. The filters separate the 6-to-18-GHz range in 2-GHz segments.

TRAK Microwave Corp., one of the Smiths Interconnect group of companies, offers half the number of filter channels, but in a much smaller housing for demanding airborne applications. The firm's model SWF001 three-channel switch filter combines a pair of single-throw, triple-throw (SP3T) switches with a trio of bandpass filters covering bands of 10.0 to 12.6 GHz, 12.6 to 16.0 GHz, and 16.0 to 20.0 GHz. The switching speed between bands is as fast as 20 ns, and the out-of-band rejection of unwanted signals is as good as 60 dB. Suitable for environments from -54 to +85C, the three-channel switch filter measures just 3.5 x 1.6 x 0.8 in. (89 x 41 x 12 mm) and weighs just 3 oz., with field-removable SMA connectors.

Microphase Corp. has long offered custom microwave switch filters complete with integrated switch drivers from 10 MHz to 22 GHz. Typically, these assemblies incorporate a single input and output, although units can also be supplied with multiple inputs and outputs depending upon a customer's requirements. Some of these multiple ports can be assigned to special purposes, such as built-in-testing (BIT) requirements. The firm will substitute switched multiplexers for solid-state switches for applications where in-band insertion loss is critical, making it possible to also achieve reduced switching times with the multiplexers. The switching speeds of these multifunction modules typically range from 10 ns to 1 s.

Endwave Corp. recently added a pair of frequency upconverters to its GaAs MMIC product lines, with models EWU1509YF and EWU1809YF developed for intermediate frequencies (IFs) from DC to 4 GHz and providing output ranges of 10.0 to 15.4 GHz and 17 to 24 GHz, respectively. Suitable for both commercial and military systems, these frequency upconverters are based on GaAs pseudomorphic high-electron-mobility-transistor (pHEMT) technology. They integrate several frequency mixers, local oscillator (LO) amplifier or frequency doubler, and variable-gain RF amplifier circuitry. The RoHS-compliant devices are housed in compact 5 x 5 mm, 32-lead, plastic-overmolded QFN surface-mount-technology (SMT) packages.

The MMDQ series of monopulse detectors from MITEQ includes what are essentially three-channel IF subsystems capable of making precision measurements on amplitude and phase for boresighting monopulse radar systems. These multiple-component modules measure the amplitude difference-to-sum ratios of received pulses over an input dynamic range from -60 to +5 dBm. The monopulse detectors are available at IFs centered at 30, 60, and 70 MHz and achieve settling times of 0.1 s or better. The detector components, which include an IF matrix, detector matrix, and three matched limiter channels, are mounted to an aluminum base plate, with power connections brought to an external barrier strip.

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The firm also offers a wide range of weatherproof modules for integration into satellite communications (satcom) systems, both commercial and military, including the model AMFW-8F-1772130-150-P2-TC-WP low-noise front-end module for use from 17.7 to 21.3 GHz. It has a WR-42 waveguide input port and female K output connector, with components protected within a lightweight aluminum-alloy housing. It measures 156 x 70 x 51 mm and weighs only 800 g. It achieves typical noise temperature of 120 K and small-signal gain of typically 62 dB.

It would be difficult to review current activity in multifunction microwave modules without some mention of Narda Microwave East and its integrated microwave assemblies (IMAs), now on the market for more than 30 years. Narda offers a range of IMA products covering 500 MHz to 50 GHz, including synthesizers, frequency upconverters and downconverters, and switched filter banks. These assemblies started life as microwave integrated circuits (MICs) for electronic-warfare (EW) systems, developed to save space and increase the level of integration within EW receivers.

As part of evolving its microwave subassembly technology, Narda developed a line of IMAs called its Ultimate MICSM products. These multifunction modules combine microwave hybrid manufacturing techniques with multilayer printed-circuit boards (PCBs) to save space through a three-dimensional (3D) design and manufacturing approach. Recently, the firm unleashed its Ultimate SMT IMA technology to integrate surface-mount-technology (SMT) components with circuits based on MIC chip-and-wire techniques. Narda's Series 80000 satcom transceivers, for example, serve X-, Ku-, and Ka-band military satcom terminals. They feature a high level of integration, with block downconverters (BDCs), block upconverters (BUCs), solid-state power amplifiers (SSPAs), and control circuitry within a compact housing.

AML, now a part of Microsemi, has developed extensive IMA technology from 1 MHz to 40 GHz for use in avionics, EW, radar, jammers, and communications systems. The firm combines a variety of technologies, such as MMICs, thin-film MICs, and discrete circuits to form its multifunction assemblies. Akon also combines technologies in its multifunction assemblies, such as its model A35-MH141 16 x 12 switch matrix for applications from 0.5 to 18.0 GHz.

The model FB-120-MPT switched filter bank from ET Industries is a compact module that houses a total of nine bandpass filters covering segments of the total frequency range from 1 to 20 GHz, switches, and switch driver circuitry. It exhibits less than 4 dB insertion loss to 1 GHz and less than 8.2 dB insertion loss through 20 GHz. The module features less than 5 ms switching time among the filters, and excellent return-loss performance (better than 11 dB) when installed in 50-O systems.

In addition to its extension lines of high-performance passive components, Anaren Microwave has shown its capabilities in higher levels of integration through its Anaren Integrated Radio (AIR) modules, which integrate supporting circuitry around a model TT1101 transceiver integrated circuit (IC) from Texas Instruments. Developed for simple integration onto two-layer PCBs, the FCC Part 15-compliant AIR modules are available at standard frequency bands, such as 433, 868, and 900 MHz, for developing quick wireless applications with minimal RF engineering. The modules measure just 9 x 12 x 2.5 mm and 9 x 16 x 2.5 mm.

Earlier this year, Anaren announced its FCC-certified A8520E24A AIR module (see figure) based on the CC8520 PurePath wireless audio system-on-chip (SoC) transceiver and CC2591 range extender from Texas Instruments and an antenna. It supports uncompressed transmit and receive of wireless digital audio (16-b resolution at 44.1/48-kHz sampling rates) for consumer and professional applications.

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