Passive Components Squeeze Into Tighter Spaces

Oct. 11, 2007
Forays into new materials and engineering techniques are enabling passive components to heighten integration and performance while downsizing to meet emerging design needs.

"Do more with less" is the mantra in much of today's electronics industry. It applies to aspects ranging from the size of a company's engineering team to the number of components in a given design. Of course, it also applies to the components themselves. Every day, passive components are being produced with the goals of achieving higher performance and greater integration in smaller packages - and, of course, at highly competitive prices. With so many new and improved components being constantly announced, one can easily overlook the intense design effort that goes into these products. Achieving such performance heights often requires material advancements that rival alchemy. The components are usually made smaller through multilayer approaches that are just as complex. For higher power, passive components demand good signal approaches with short signal traces and low insertion loss. Impressively, these feats are simultaneously achieved by many of today's passive-component makers.

One path to shrinking circuit and system level designs lies in low-temperature co-fired ceramic (LTCC) materials. A number of companies have been leveraging LTCC's attributes in components of all types. Barry Industries (Attleboro, MA) takes a unique approach by delivering a bundle of services through its LTCC operation. This company supplies everything from foundry services to complete design and build with everything in between. Barry's LTCC foundry has on-site RF-microwave design, measurement, and analysis experience up to 60 GHz. With these capabilities, the company can simulate a design's RF and microwave performance before fabrication. It also can check performance as part of the fabrication process. By lever aging in-house thermal testing and imaging, Barry can verify the performance of its own designs as well as those of its customers. It also is able to make both tools and parts internally in its captive machine shop. For a lower-cost option, the company even offers N/Au plating of LTCC.

Mini-Circuits (Brooklyn, NY) has used the benefits of LTCC technology to miniaturize numerous passive components including mixers and power splitters/combiners. The firm's model SIM-U742MH+ mixer, for example, uses a diode quad on an LTCC substrate to achieve an upconverter mixer measuring just 0.2 x 0.18 x 0.087 in. (5.1 x 4.6 x 2.2 mm). It operates with local-oscillator (LO) signals from 2300 to 7400 MHz and intermediate-frequency (IF) input signals from 0.1 to 3300 MHz. In addition, it provides RF output signals from 2300 to 7400 MHz with 8-dB typical conversion loss.

Anaren (E. Syracuse, NY) is so highly committed to LTCC technology that it has established Anaren Ceramics, Inc. for the design and manufacture of advanced high- and low-frequency circuits based on ceramic materials. The facility offers "built-to-print" services as well as full computer-aided-engineering (CAE) design capabilities supported by extensive test services. Still, Anaren may be best known for its lines of miniature Xinger(R) passive components, such as the model BD0826J50200A00 50Ω to 200Ω balanced-unbalanced (balun) transformer. Designed for applications from 800 to 2600 MHz, it measures just 0.08 x0.05 in. (2.00 x 1.25 mm) but handles as much as 2 W input power. Insertion loss is typically 1 dB while amplitude and phase unbalance are controlled to typically 0.4 dB and 6 deg., respectively. The surface-mount balun is suited for a range of wireless systems including CDMA, GSM, UMTS, and wireless local- area-network (WLAN) circuits.

As an alternative to LTCC, Merrimac Industries (West Caldwell, NJ) developed a multilayer technology known as Multi-Mix®. It is based on multiple fusion bonded PTFE substrate layers that form a self-shielding structure, which can contain both active and passive components. Multi-Mix supports the fabrication of components and integrated assemblies through 100 GHz at a fraction of the size of conventional microwave integrated- circuit (MIC) technologies. It has been used for a variety of standard components, such as hybrid couplers, filters, and power dividers/combiners as well as highly integrated assemblies like switch-filter banks, instantaneous-frequency-measurement (IFM) receivers, and beamforming networks.

Of course, not all impressive passive-component achievements rely on LTCC. Johanson Manufacturing (Boonton, NJ), for example, recently added high power terminations to its capacitors and other passive product lines. The company's model TF800BB14 high-power termination features maximum VSWR of 1.90:1 from DC through 2 GHz. It handles 800 W typical power (1 kW maximum power) across that frequency range. For lower-power, higher-frequency applications, the model TF020BB3R/L/C terminations operate from DC to 4 GHz with 100-W powerhandling capability and less than 1.40:1 VSWR across the frequency range.

Voltronics Corp. (Denville, NJ), a long-time supplier of high-performance trimmer capacitors, also lists extensive lines of non-magnetic chip capacitors for demanding medical and scientific applications. The company offers four different families of non-magnetic chip capacitors. The 5 Series non-magnetic chip capacitors measure 0.055 x 0.055 in. with a total capacitance range of 0.1 to 100.0 pF. In contrast, the 11 Series chip capacitors measure 0.110 x 0.110 in. and are available in a total capacitance range of 0.1 to 1000.0 pF.

RLC Electronics (Mount Kisco, NY) recently launched a line of high-power directional couplers that features lower passive intermodulation (PIM) than the company's standard coupler products. These low-PIM devices utilize special design configurations that minimize mechanical contacts in the signal path and signal current densities throughout the device. To ensure maximum levels of cleanliness and material purity, special manufacturing processes also are used along with materials that have highly linear electrical properties at high signal levels. Typical third-order PIM levels are better than -163 dBc (-120 dBm for two +43-dBm tones). These couplers can be supplied as single or dual directional types for most of the popular communication bands. Coupling values may be as low as 10 dB with main line frequencies out to 13 GHz and power capability of 500 W average and 10 kW peak.

ARRA, Inc. (Bayshore, NY) owes much of its longstanding success as a component supplier to the ideals of its late leader, Florence Isaacson (see "Living Life Like A Microwave Legend," August 2007, p. 17). The company is a seasoned producer of high-quality waveguide and coaxial passive components including rotary attenuators, couplers, tees, and bends. The model 4-5194-10 broadband 10-dB SMA coupler, for example, handles 50 W average RF power and 3 kW peak power from 2.6 to 5.2 GHz. It exhibits 20-dB directivity with maximum insertion loss of 0.2 dB. Over a frequency range of 0.5 to 2.0 GHz, the model 2-3174-6 coupler offers 6-dB coupling with coupling flatness of ±1.0. Its frequency sensitivity is ±0.75 dB while directivity is a minimum of 23 dB. Maximum VSWR is 1.20:1 for both primary and secondary ports. Insertion loss is 0.40 dB maximum.

Dalicap Corp. (Huntington Station, NY) offers lines of multilayer capacitors for both power and RF applications including non-magnetic products. These products exhibit Q performance above 10,000 and are available in four case sizes. The A case, which measures 0.055 x 0.055 in., is operational up to 300 WVDC. The 0.110 x 0.110 in. B case operates to 1000 WVDC. The C case measures 0.225 x0.225 in. It is operational up to 5000 WVDC. Finally, the E Case measures 0.390 x 0.390 in. and is operational up to 7200 WVDC. This series is available in two dielectric styles: the 10 series (P90) or 70 series (NPO). The company offers sample kits including the DKDLC10B03, which contains 16 values ranging from 100 through 1000 pF.

Werlatone, Inc. (Brewster, NY) is known for making exceptional highpower components. It supplies broadband, high-power RF devices that operate between 10 kHz and 4 GHz at levels to 50 kW. The C7118 is one of the company's line of 6-dB directional couplers. It operates over a 30-to-90-MHz frequency range while handling 400 W of continuous- wave (CW) power. Its insertion loss is 0.2 dB while directivity is 20 dB. The company also offers wideband dividers and combiners/dividers. The D5674 two-way combiner spans 0.01 to 250 MHz while handling 100 W of CW power. Insertion loss and isolation are 1.5 and 18 dB, respectively.

MITEQ, Inc. (Hauppauge, NY) recently announced a 90-deg. hybrid coupler, model M-23-183-91WS. This device spans 2 to 18 GHz. VSWR is 1.7:1. Insertion loss is 2.0 dB maximum while isolation is a minimum of 15 dB. The coupler includes SMA female connectors and has phase unbalance of better than ±10 deg. Amplitude unbalance is better than 1.5 dB. This unit measures 1.91 x 1.11 x 0.44 in. (Fig. 1).

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At the end of April, Innovative Power Products (Holbrook, NY) debuted the model IPP-2069 90-deg. hybrid coupler. This 3-dB coupler covers the 100-to-500-MHz frequency range. It can combine two signals of up to 150 W CW of total input power. Insertion loss is less than 0.5 dB while phase unbalance is better than ±6 deg. VSWR is less than 1.30:1. The coupler's amplitude unbalance is better than ±0.75 dB. The model IPP-2069 offers greater than 17 dB of isolation. It is housed in a 3.3 x 1.5 x 0.23-in., drop-in style package.

A 900-MHz bandpass filter from Integrated Microwave (San Diego, CA) targets the industrial-scientific-medical (ISM) band. The filter features a 23- MHz bandwidth centered at 914 MHz. Over the passband, it has insertion loss of less than 1.6 dB. Signals 20 MHz or more from the passband are attenuated more than 30 dB. To achieve such performance in a compact, through-hole package, this filter uses ultra-high 'Q' ceramic resonators with an elliptic response and eight poles. It measures just 3.82 x 0.50 x 0.95 in. SMT, connectors, and hermetic versions also are available.

A family of thin-film, low-pass filters from State of the Art, Inc. or SOTA (State College, PA) was designed to eliminate the need for multiple components where space use is critical (Fig. 2). The filters, which are part of the company's high-frequency product line, come in a sub-miniature case size measuring 0.150 x 0.100 x 0.025. They are available on a 99-percent-alumina substrate that was constructed using high-stability, thin-film planar technology. 50Ω terminations are available for either solder or epoxy mounting. These devices are available with passband cutoffs at 5.5, 7, and 8 GHz. Maximum rejection is greater than 16 dB. The filters boast VSWR characteristics of less than 1.4:1 with insertion loss of less than 0.5 dB. The filters are available in several standard designs and custom cut-off frequencies including high-reliability screening. The LPF line is suitable for many different applications to reduce and eliminate unwanted harmonics in telecommunications systems. Examples include satellite receivers, mobile communications, Global Positioning Satellite (GPS) systems, WLANs, and WiMAX.

WiMAX also is among the target applications of a line of ceramic filters from MtronPTI (Yankton, SD). That line marks the company's first foray into ceramic filters. It features products with frequencies from 300 MHz to 6 GHz with a 1- to 40-percent bandwidth. The ceramic filters are a good fit for base stations, up/downconverters, receivers, transceivers, very-smallaperture and satellite terminals, and more. The 3.5-GHz CF2510R, for example, boasts 300-kHz bandwidth. The model CF2510R also features 2.5 dB insertion loss, 1.0 dB of ripple, and 13 dB return loss. The 50Ω terminated device provides 60 dB of attenuation at 3.95 and 3.1 GHz. The surfacemount package measures 26.5 x 12 x 6.3 mm. This product line also will include mono-block duplexers, which are configured with several resonators.

A line of 6-GHz RF components from JFW Industries (Indianapolis, IN) also was spawned for the latest wireless, WiFi, and WiMAX networks. These high-performance products include DC-to-6-GHz fixed attenuators with N or SMA connectors, DC-to-6-GHz rotary attenuators, 0.2-to-6-GHz digitally programmable attenuators (TTL, Ethernet, and RS-232 compatible), and 2-to-6-GHz power divider/combiners.

In the divider arena, Rojone Pty. Ltd. (Ingleburn, Australia) recently released the broadband, two-way AMA-2860-2N. This divider was designed for multichannel operation from 0.8 to 6.0 GHz with -140 dBc intermodulation distortion when tested with two +43-dBm tones. It is designed to handle 10 W maximum power at 1.50:1 VSWR and 50 W maximum power at 1.20:1 VSWR. The input return loss is typically 20 dB through 3 GHz and 17 dB from 3 to 6 GHz. Output return loss and isolation are typically 20 dB. Insertion loss is less than 0.3 dB through 3 GHz and less than 0.6 dB through 6 GHz.

For technicians working at tower tops, higher integration can truly translate into fewer parts that could get dropped. The 700-W reactive splitters from MECA Electronics (Denville, NJ) flaunt a unique design that eliminates the need for extraneous mounting hardware (Fig. 3). Even for the largest coaxial cables, unobstructed access to connector ports promises easy installation with no additional mounting hardware. Because they cover all wireless bands from 0.8 to 2.7 GHz, these splitters are well suited for both tower and in-building applications. The rugged splitters are available in two-way, threeway, 7/16 DIN, Type-N, and SMAfemale configurations. The R2S-1.9000- M01 SMA-female power splitter, for example, handles an average of 100 W of power. Its insertion loss is typically 0.30 dB with a maximum of 0.40 dB. Maximum amplitude unbalance is 0.2 dB while phase unbalance is 2 deg. maximum. Input VSWR is 1.10:1 typical and 1.20:1 maximum.

Five series of shielded surface-mount inductors have been designed for applications where component height and printed-circuit-board (PCB) real estate is limited. The 4500, 4600, 4700S, 4800S, and 4900S series from C&D Technologies (Mansfield, MA) boast inductance values from 0.28 μH to 1.0 mH (Fig. 4). The 4600 series, for example, is rated up to 8.7 A. It is offered with inductance values between 0.28 μH and 1.0 mH. The lower-profile 4500 series has the same inductance values and a maximum 8-A rating. Both devices have a footprint of 7.3 x 7.3 mm. Overall height is 3.55 mm for the 4500 series and 4.55 mm for the 4600 series.

This summer saw the announcement of a series of resistors with an alumina ceramic layer that separates the resistance element and mounting tab. This approach results in low thermal resistance while guaranteeing high insulation resistance between the terminals and metal backplate. With their resulting low inductance, the MHP Series TO-247 resistors are a good fit for high-frequency and high-speed pulse applications (Fig. 5). Hailing from TT electronics' IRC Advanced Film Division (Corpus Christi, TX), these 100-W and 140-W resistors feature a resistance range of 0.01Ω to 220Ω and an inductance value of less than 50 nH. Their voltage rating is 700 V. Absolute tolerances are to ±1 percent and ±5 with absolute TCRs to ±100 ppm/°C.

Although these components offer only a narrow glimpse into this arena's numerous and constant innovations, their diversity signals the many needs that these products fulfill. Passive components may not get any of the glory for their parts in higher-level RF and microwave systems. Without these workhorses, however, products such as radar, communications, and electronic-warfare (EW) systems simply would not exist. Today's passive-component makers continue to re-invent their products to make sure that they are keeping up with the latest technologies, environmental requirements, and performance specifications. Thanks to their dedication, the microwave industry can consistently achieve new performance heights.

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