- Buyers Guide
5G and IoT Supplement
GaAs MMIC Switch
The model SWM-6000-1DTU option 011 is an absorptive/non-reflective SPST switch that operates from 10 MHz to 6 GHz (other frequencies available). Insertion loss is < 1.25 dB at 10 MHz and < 3.5 dB at 6 GHz. Isolation is > 100 dB at 10 MHz and > 30 dB at 6 GHz. SWR is 1.5. Speed is < 12 ns delay on and < 8 ns delay off. Video transient is < 42 mV P-P at 300 MHz BW and 13 mW P-P at 20 MHz BW. Supply is +5 V at < 3 mA and -5 V at 4 mA. Size: 1.4" x 0.8" x 0.4". Weight: < 1.0 ounce typical.
American Microwave Corp., Frederick, MD (301) 662-4700. Circle No. 216
The HubCap is a capacitor assembly that delivers virtually resonance-free operation from 16 kHz through to 40 GHz. The product utilizes the company's patented broadband microwave capacitor in conjunction with a miniature multilayer capacitor to create an ultra-broadband coupling function in an 0402 package, with a maximum insertion loss of 0.75 dB and with a worst-case return loss of 15 dB. Also, the device has a ±15 percent temperature coefficient of capacitance over a temperature range of -55° to +125°C.
American Technical Ceramics, Grafing, Germany +49 8092 851086. Circle No. 266
This MMCX series of connectors presents electrical micro-interruptions in case of vibrations, or accidental movements of the connection cables. This new type of mechanism in the male body provides the following advantages: guarantee of a strong and continuous contact in any operating condition, the outer connection will always be free from dirt as a result of suitable self-cleaning elastic springs, the number of the possible connection/disconnection operations results are widely increased, and this product was introduced on the male connectors only. The coupling operations with the relevant females and the resulting characteristics are in any case guaranteed, therefore avoiding any modification on the existing equipment.
Compel Electronics SpA, Cornate d'Adda, Italy +39 039 61001. Circle No. 265
The model 4IMM38-9A is a microstrip isolator for the 37 to 40 GHz wireless band with reduced size and improved performance. Insertion loss has been reduced to 0.7 dB with over 20 dB isolation. The isolator is still capable of handling 2 W of forward power with a 1 W load over the full temperature range of -30° to +70°C. The model 4IMM38-9A is available for production requirements in any quantity. Size: 0.131" x 0.197" x 0.138".
Dorado International Corp., Seattle, WA (206) 574-0900. Circle No. 267
The model AT-75-30 is a 75 30 dB coaxial RF attenuator for use from DC to 0.75 GHz. This model is available with BNC connectors. It has 0.75 dB accuracy to 0.5 GHz and 1.5 dB accuracy to 0.75 GHz. SWR is 1.2 nominal and 2.0 maximum at the highest frequency. This commercial unit has nickel plated connectors and gold plated contacts, which mate with 50 connectors. Resistor networks are aged for stability. Price: $16.50. Delivery: stock to 30 days ARO.
Elcom Systems Inc., Boca Raton, FL (561) 883-1945. Circle No. 218
The model D3-21FD is a three-way wideband reactive power splitter using 7-16 mm DIN connectors. It has good bandwidth covering 380 to 2200 MHz, that includes Tetra, SMR/PMR and all cellular bands, including the 700 MHz and 3G (UMTS). The splitter is ideal for designing passive in-building wireless distributed antenna systems now being required to meet homeland security issues. The high reliability required of such DAS systems is most easily met with a passive network approach. The low loss of reactive components such as the D3-21FD, help make the passive design realizable without recourse to amplifiers or other active components. Such a passive approach enhances reliability, cuts installation cost and has a high communications survival potential in an emergency situation.
Microlab/FXR, Livingston, NJ (973) 992-7700. Circle No. 222
These low SWR termination resistors are ideal for applications as isolator circuits in RF and microwave amplifiers and antenna systems. The geometry of the resistor chips is designed to optimize high frequency performance and high power capacity. Power handling for the devices is 150 W. Minimum reflection is obtained by presenting a low SWR to a matched system while maintaining 50 W of resistance. The chips are fully surface-mountable. The low SWR chip components are available in either long or short dimension lead configuration. The termination operating performance is between 5 and 6 GHz. Size: 0.375" x 0.250" x 0.040".
International Manufacturing Services Inc., Portsmouth, RI (401) 683-9700. Circle No. 220
The zero bias Schottky detectors include a rugged type N male input connector. The operating frequency is 0.01 to 18.5 GHz. Maximum SWR is 1.15 to 4 GHz, 1.20 to 15 GHz, 1.4 to 18.5 GHz. Frequency response is < ±0.3 dB to 12.4 GHz and < ±0.6 dB to 18 GHz. Low level sensitivity is 0.5 mV/mW. Output polarity: negative. Customer choice of output connectors: SMC jack, female BNC, female SMA. Delivery: stock to four weeks.
Krytar, Sunnyvale, CA (408) 734-5999. Circle No. 221
The model N828ANM2 is an SP8T absorptive switch. It combines a wide frequency range of 1 to 18 GHz, high isolation of 50 dB minimum, with low insertion loss of 4.5 dB maximum.
MITEQ Inc., Hauppauge, NY (631) 436-7400. Circle No. 223
This SMC series one inch square size surface-mount coplanar, circulators and isolators are for high power applications. The circulators are distinguished by good high power performance in congested multi-carrier environment. Features include: inherently coplanar structure for surface-mount applications, compliant with pick-and-place assembly process, magnetically shielded, reflow solder compatible, low loss, high power and temperature stable design. With third order intermodulation better than -75 dBc, the SMC series is suitable for AMPS, DECT, GPS, PCS, DCS, UMTS and IMT 2000. Available frequencies include 880 MHz to 2.5 GHz.
Renaissance Electronics Corp., Harvard, MA (978) 772-7774. Circle No. 269
This range of SAW filters targets the ISM bands: 433, 869 and 915 MHz. Designed for various applications including automotive, security and access and home convenience, these high performance devices are available in standard packages of 3.8 x 3.8 mm2 or 3.0 x 3.0 mm2.
Temex, Paris, France +33 (0) 1 46 90 23 33. Circle No. 224
This series of EIA connectors is offered in two sizes as plugs, jacks, receptacles and adapters for use with multiple coaxial cables. The EIA connectors are offered in 7/8" and 1-5/8" sizes that fit on flexible coaxial cables from 0.5" to 1.2" O.D. Featuring silver plated beryllium-copper inner conductors, with Teflon" dielectrics and nickel or silver plated bodies, these high power connectors can be supplied as straight or right angle plugs, receptacles and jacks. Available separately or as finished cable assemblies, EIA connectors operate at frequencies from DC to 3000 MHz, with a peak power rating of 132 kW, average power rating of 35 kW at 13.56 MHz, an 11 kV DC voltage rating, and exhibit 50 impedance and 1.15 SWR. Price: $75.00.
TRU Corp., Peabody, MA (800) 262-9878. Circle No. 227
The model 890027 is a GSM front-end antenna switch module designed for use in next-generation, low profile multi-band GSM, GPRS and EDGE phones. The module integrates antenna switching and low pass filtering functions with increased electro-static discharge protection needed for dual-band GSM, GPRS and EDGE phones. The surface area is 45 percent smaller than low temperature co-fired ceramic solutions with a 33 percent height reduction. Size: 3.7 x 3.2 x 1.2 mm.
TriQuint Semiconductor Inc., Hillsboro, OR (503) 615-9000. Circle No. 226
The model PE2-44-12-1R5NF-15-SFF is an octave band amplifier that offers 46 dB typical gain from 1 to 2 GHz. The gain flatness is better than ±1.5 dB, noise figure is < 2 dB and the OP1dB is > 10 dBm. SWR in/out is 2.0 maximum and the current is 250 mA at +15 VDC maximum. This amplifier can be supplied in many choices of housings. Other gain levels are available.
Planar Electronics Technology, Frederick, MD (301) 662-5019. Circle No. 233
These three cellular band tower top low noise amplifiers (TTLNA) include the fullband (25 MHz), A-band (22.5 MHz) and B-band (14 MHz) system requirements. Configured as a full-duplex configuration, the cellular band TTLNA's feature advanced psuedo-elliptic filter response for low loss/noise figure and good rejection contributing to the units low typical noise figures of < 1.6 dB for fullband, < 1.7 dB for A-band and < 1.9 dB for B-band, while simultaneously offering sharp rejection for all bands. The product also utilizes e-PHEMT LNA technology, providing low noise figure and high third-order input intercept of +12 dBm minimum. The cellular band TTLNA's offer automatic bypass operation when either LNA transistors fail, or when the supply voltage falls outside of normal operating range. Size: 11.6" x 8.7" x 3.5", including mounting feet and 7/16-DIN connectors. Weight: 10 lbs nominal.
K&L Microwave Inc., Salisbury, MD (410) 749-2424. Circle No. 230
The model NBL00419 is a 4 to 8 GHz low noise amplifier for use in fixed satellite service, defense radar and communications as well as cable TV and broadcast auxiliary. The unit has a gain of 30 dB, noise figure of 1.7 dB, with a 1 dB compression point of 16 dBm at room temperature. It operates at -30° to +70°C with DC supply voltage of +10 to +17 V. Custom designs and hermetic sealing are available.
Nextec Microwave and RF Inc., Santa Clara, CA (408) 727-1189. Circle No. 231
The model PA-09402-14-32DBM is a 900 MHz to 4.2 GHz frequency range high power amplifier/coupler (frequency ranges from 0.3 to 18.0 GHz are available). The amplifier has 14 dB of gain minimum with a saturated output power of +31.5 dBm while operating with a maximum RF input power of +23 dBm. This device also possesses a coupled output port. DC power supplies are -5 and +15 VDC. Size: 4.0" x 3.0" x 0.75".
Planar Monolithics Industries, Frederick, MD (301) 631-1579. Circle No. 234
The QBH-2001 and QBH-2003 low noise amplifiers are complete amplifiers ready to plug-and-play, saving time and money. With their metal cover, they are a good choice to minimize or eliminate the need for isolation covers on boards. The QBH-2001 offers PCS and broadband coverage and has a 0.9 dB noise figure and +34 dBm OIP3. The QBH-2003 covers cellular band with a 1.0 dB noise figure and +32 dBm OIP3.
REMEC Inc., Del Mar, CA (321) 727-1838. Circle No. 268
The RMPA2550-252 is a dual frequency band power amplifier designed for high performance WLAN applications in the 2.4 to 2.5 GHz and the 5.15 to 5.35 GHz frequency bands. The single low profile 20-pin 3 x 4 mm package with internal matching on both input and output to 50 minimizes next level PCB space and allows for simplified integration. The two on-chip detectors provide power sensing capability while the logic control provides power saving shutdown options. The PA's low power consumption and good linearity are achieved using the company's InGaP heterojunction bipolar transistor technology.
Raytheon RF Components, Andover, MA (978) 684-8900. Circle No. 235
The model RF3146 is a third-generation of the company's PowerStar™ GSM power amplifier modules with integrated power control. The RF3146 is designed using the company's new Lead Frame Module™ (LFM™) packaging technology and features RFMD's proven integrated power control technology, both of which are patent-pending and enable higher levels of integration, reduced cost and enhanced performance. The RF3146 is designed for use as the final RF amplifier in single- and multi-band GSM, DCS and PCS handheld digital cellular equipment and other applications in the 824 to 849 MHz, 880 to 915 MHz, 1710 to 1785 MHz and 1850 to 1910 MHz bands, and is also offered as part of RFMD's POLARIS™ TOTAL RADIO™ solution. The PA module's fully integrated silicon CMOS power control loop meets all spectrum and burst-timing requirements, with 50 input and output terminals, which simplifies engineering effort and shortens cycle times. Size: 7 x 7 x 0.9 mm.
RF Micro Devices Inc., Greensboro, NC (336) 664-1233. Circle No. 236
The model SM2527-44L is a solid-state GaAs FET amplifier designed for the MMDS market. Using a built-in linearizer, it provides ultra linear performance for rigorous system requirements. The minimum P1dB is +44 dBm, with an OIP3 of 63 dBm minimum. Typical linear gain is 55 dB. Features include a single DC supply voltage of +12 V, over/reverse voltage protection, thermal protection with auto reset, temperature compensation, logic on/off control and an integral output isolator. Available options include forward/reverse power detection and RF sampling.
Stealth Microwave, Trenton, NJ (609) 538-8586. Circle No. 237
The model AH117 is a high gain, high dynamic range 0.25 W driver amplifier, and the model AH210 is a 1.0 W device. Both models have high gain and good linearity capable of meeting system-critical ACPR performance requirements: at any given output power these amplifiers will maintain good adjacent and alternate channel power rejection levels. These amplifiers operate directly from a single +5 V bias supply and are capable of class A/B operation for improved efficiency.
WJ Communications Inc., San Jose, CA (800) WJ1-4401. Circle No. 238
The model AM 100MX-CU GaAs FET is part of a series of GaAs MESFET power products. This device has a total gate width of 10.0 mm and is offered in a specially designed ceramic package with straight leads and flange in a drop-in mounting style. The flange at the bottom of the package serves simultaneously as DC ground, RF ground and thermal path. Typical performance for AM 100MX-CU device at 4.0 GHz (TA=25°C) when VDS=7 V and Ids=0.5Idss is: P1dB=35 dBm; Eff at P1dB=37 percent; gain (small signal) 10 dB, IP3=48 dBm. It is well suited for wireless communications applications including WLAN, MMDS/MDS, PCS, base stations, repeaters and hyperlan.
Amcom Communications Inc., Clarksburg, MD (301) 353-8400. Circle No. 240
The MLP 7100 series of limiter diodes is comprised of application specific PIN devices that are specially fabricated to have particularly low loss (< 0.1 dB) and fast recovery time (< 5.0 ns) over a frequency range of 100 MHz to 22 GHz. Designed for use in both active and passive limiters, a unique intrinsic region design gives engineers the ability to choose from various "I" region thicknesses and capacitance levels. This allows them to design without compromise because they can order the precise device that will work best for their particular power in (Pin > +70 dBm) and leakage out (Pout < +19 dBm) requirements. They are available in many package styles including chip form, glass, ceramic and surface mount. They are ideally suited for use in waveguide, coax, microstrip or stripline.
Micrometrics, Londonderry, NH (603) 641-3800. Circle No. 264
The RO3000® high frequency materials are ceramic-filled PTFE composites intended for use in commercial microwave and RF applications. This family of products was designed to offer good electrical and mechanical stability at competitive prices. This series of laminates are PTFE-based circuit materials with mechanical properties that are consistent regardless of the dielectric constant selected.
Rogers Corp., Rogers, CT (860) 774-9604. Circle No. 242
The G1111M and the G1010M are discrete semiconductor packages in a low cost hermetic surface-mount configuration for high reliability applications. The packages are available with lead profiles meeting JEDEC standards. They are assembled using a glass-to-metal seal process, resulting in a rugged and reliable package supplied at attractive pricing. The hermetic seal provides enhanced reliability for the semiconductor device and offers protection from environmental conditions, meeting military standard requirements. The advantage is the availability of a hermetic package at off the shelf pricing. Size: G1111M 3 x 3 mm; G1010M 2.5 x 2.5 mm. Price: $2.00 (10,000).
StratEdge, San Diego, CA (858) 569-5000. Circle No. 243
The model 8000 is a high speed thermosonic ball-and-stitch wire bonder. This bonder has a large 12" x 6" (300 x 150 mm) X-Y bond area so it can handle large hybrid and multichip modules as well as the smallest devices. Placement accuracy and repeatability of better than ±5µm and a bond pitch of 70µm improve production yields and eliminate sources of variation in the manufacturing process. The model 8000 provides a high level of positioning accuracy, along with highly repeatable ball formation to enable tight spacing between wires. Typical uses for the model 8000 will be wire bonding for microelectronic packaging including most semiconductor-based interconnect applications.
Palomar Technologies, Vista, CA (760) 931-3600. Circle No. 244
This version 6.1 of LINMIC is a microwave/RF IC design suite that has further improved in accuracy, convergence and robustness of the harmonic balance algorithm for the simulation of nonlinear circuits with harmonic and with digitally modulated excitation signals. The 2.5D PEEC engine for the simulation and design of multilayer components like LTCC baluns now supports automatic layouts optimization for user-defined electrical specs. The 2D engines for the simulation of single and multiple-coupled strips in single and multilayer dielectrics now offer additional post-processing and graphical output. The GUIs have been revised and extended for ease and convenience of input and output.
AC Microwave GmbH, Aachen, Germany +49 241 879 3022. Circle No. 245
Ansoft Designer™ SV is a free, full-featured linear simulator for high frequency microwave and radio frequency circuit and system design. Designer SV is available for download at www.ansoft.com/ansoftdesignersv and provides engineering professionals and students with linear frequency-domain circuit simulation technology and a design environment that are comparable to that of the commercial version of Ansoft Designer.
Ansoft Corp., Pittsburgh, PA (412) 261-3200. Circle No. 246
This service release of CST Microwave Studio® (CST MWS) and CST DESIGN STUDIO™ (CST DS) includes several new functionalities since the release of version 4.0. The most significant features include: numerous improvements in the calculation of farfields including Ludwig Transformations, nearfield calculations, time domain probes, phase plots and phase centre calculations. Modal waveguide ports can be defined inside the calculation domain. The new general voxel import allows engineers to input or create their own models for SAR calculations in addition to using the commercially available anatomical data set "HUGO." Enhanced post-processing capabilities include new automatic schemes enabling easy, versatile evaluation of parameter studies, field integration over arbitrary faces, and the application of the AR filter to probe signals, implementation of a direct, multi-frontal frequency domain solver with fast frequency sweep, improved periodic boundary conditions in the frequency domain and improved 2D and 3D import options.
Computer Simulation Technology, Darmstadt, Germany +49 (0)6151 7303-0. Circle No. 247
The silicon-based MRO-100™ is a multi-frequency oscillator designed to replace multiple quartz crystal oscillators, significantly cutting wireless component cost, power consumption and shrinking wireless architecture. The production version of the MRO-100 will be manufactured using mainstream silicon technology processes and wafer-level packaging, as well as convenient testing methodologies, to derive the required cost benefits of volume manufacture. The technology relies on the company's patented micro-resonator technology, which is based on micro-machined silicon parts designed to resonate at certain frequencies. Multiple resonators, which are measured in microns, can be deployed on a single die, each resonator operating at a differing frequency. The micro-oscillator, whose function is to provide a timing signal, is created by integrating the resonator with a small IC that furnishes an electronic interface to the rest of the system. The micro-resonator architecture offers several additional benefits, including RFIC integration potential, extended tunability compared to quartz and Q factors of greater than 10,000. Size: 3 x 3 mm.
Discera Inc., Campbell, CA (408) 376-4150. Circle No. 249
The model FOX923E is a temperature compensated, voltage-controlled crystal oscillator (TCVCXO) which is ideal for applications where size and cost are critical, such as in the portable, handheld and wireless markets. The frequency range of the FOX923E is 13 to 26 MHz, with a supply voltage range of 2.85 to 3.15 VDD and an initial frequency tolerance of -0.5 to +0.5 ppm at 25°C ±2°C. Standard operating temperature is -20° to 75°C. The new TCVCXO's frequency stability is -2.5 to +2.5 ppm over the temperature range and -0.2 to +0.2 ppm over the supply voltage change of 3.0 V ±5 percent. Size: 3.2 x 2.5 x 1.2 mm. Price: $1.99 (10,000). Delivery: eight weeks ARO.
Fox Electronics, Fort Myers, FL (888) GET-2-FOX. Circle No. 252
This synthesized digitally tuned oscillator was designed specifically for EW applications. The SDTO series is based on direct analog techniques combined with DDS capability for fine frequency resolution. This series is ideally suited for EW systems where fast switching speeds and linear FM modulation are of primary importance. The SDTO series can be customized to meet special applications. Size: 5" x 3.8" x 1.75".
Elcom Technologies Inc., Rockleigh, NJ (201) 767-8030. Circle No. 250
The model SP6618 is a broadband fast indirect synthesizer (FIS). The low phase noise FIS was designed to replace YIG-based synthesizers. Power output is +10 dBm, minimum. Frequency step size is 1 MHz and the settling time is 100 µs, maximum. The phase noise at 18 GHz is -74 dBc/Hz at 100 Hz offset, -86 dBc at 1 kHz offset, -103 dBc/Hz at 10 and 100 kHz offset, -105 dBc at 1 MHz offset, -125 dBc at 10 MHz offset and -140 MHz offset. Harmonics are -40 dBc, maximum and spurious are -60 dBc, maximum. The model SP6618 is controlled via a parallel interface. Size: 6.3" x 11.8" x 1.9".
Herley Industries, Farmingdale, NY (631) 630-2020. Circle No. 254
The model D620 is a broadband dual-channel frequency synthesizer which contains two fully independent high performance, low phase noise, fast switching frequency synthesizers. Each synthesizer covers 1 to 620 MHz and is housed in the single rack or bench-top form-factor. For each fully independent channel, frequency control is via a 50-pin parallel interface (TTL-level logic) which is pin and programming compatible with the remote interface standard on current synthesizers. The instruments feature fast frequency switching of 20 µs maximum, low phase noise of -110 dBc/Hz at 1 kHz offset and low spurious output of -65 dBc, 1 to 310 MHz; -60 dBc, 310 to 620 MHz.
Programmed Test Sources Inc., Littleton, MA (978) 486-3400. Circle No. 256
The 2400 series microwave synthesizer is a general purpose microwave synthesizer that delivers both low phase noise and fast frequency switching capabilities simultaneously. The low noise, high power and fast switching features of the 2400 series synthesizer make it a good test solution for a wide range of CW, swept and stepped frequency applications in both R&D and manufacturing environments. The 2400 series is capable of switching frequency in less than 400 µs, over the entire frequency range, making the 2400 ideal for test applications demanding high throughput, such as antenna characterization, T/R module evaluation or RFIC manufacturing. In addition, the 2400's low phase noise makes it suitable for serving as a low jitter clock as well as a source for low noise frequency conversion. Price: $17,000.
Giga-tronics Inc., San Ramon, CA (800) 726-4442. Circle No. 253
The BiM1 VHF transceiver modules are primarily for a wide range of long range, low power, bi-directional data link applications. This makes the BiM1 ideal for low power applications where existing wideband modules do not have sufficient range. The BiM1 is adapted for a wide range of low power and bi-directional wireless connectivity applications in battery-powered and hand-held equipment. These include remote meter reading, PDAs, organizers, laptops, hand-held terminals, EPOS equipment, barcode scanners, data loggers, in-building/outdoor environmental monitoring and control, high end security and fire alarm systems, and also vehicle data download/upload systems. Size: 33 x 23 x 10 mm.
Radiometrix Ltd., Hertfordshire, England +44 20 8428 1220. Circle No. 258
The Picoprobe® model 35 is a probe that has been engineered to meet the stringent demands of advanced high frequency circuit designers. This probe combines full DC capability, rise/fall times of 14 ps and a nominal loading input impedance of 1 M shunted by 0.05 pf. Signal attenuation is 10:1 with a 50 oscilloscope input. The model 35 achieves its bandwidth using just one probe point, which greatly simplifies internal node testing without sacrificing performance. An assortment of user replaceable probe tips are available for a variety of probing needs. The model 35 is powered by the PS-3 power supply.
GGB Industries Inc., Naples, FL (239) 643-4400. Circle No. 263
The Seven.Five multi-band, multi-technology RF scanner is primarily for wireless field-test applications. Capable of lightning-fast scans (up to 3000 channels per second) in multiple frequency bands, with multiple technologies, the Seven.Five scanner decodes DVCC, BSIC and PN decoding simultaneously. The scanner offers spectrum analyzer-type measurements and full baseband decoding for GSM 850/900/1800/1900, GPRS, IS-136, CDMA2000 and WCDMA. The scanner consumes less than 7 W and has a network-locked frequency accuracy of ±0.1 ppm. The scanner has full ESD protection, is CE Mark compliant and includes external USB connections. Price: $10,000.00. Delivery: six to eight weeks ARO.
Comarco Wireless Test Solutions, Irvine, CA (949) 599-7400. Circle No. 261
The model A048A connector gage kit is designed to measure 1.85/2.4 mm connectors with either female or male interfaces. Repeatability of ±50 millionths of an inch (±0.00005 inch) is achieved by using digital indicators with 0.0001 inch graduations and tightly controlled tolerances on all machined parts. The models A048A1 (female) and A048A2 (male) connector gage assemblies use a "thread-on" design that simulates actual mating conditions allowing high accuracy measurements. Critical contact pin locations can be read directly on the digital indicator. Centering sleeves are provided for measuring beadless air lines and 2-port standards. Flush setting sliding loads are easily accomplished using the A048A gages.
Maury Microwave Corp., Ontario, CA (909) 987-4715. Circle No. 262
Get access to premium content and e-newsletters by registering on the web site. You can also subscribe to Microwave Journal magazine.