Matching a component to an application can be tedious and even unnerving at times. No matter how well versed a high-frequency engineer is in terms of the latest components, few if any can understand how some components can fit into a circuit or system better than others. Fortunately, the ready availability of the World Wide Web and high-speed Internet access, coupled with ever-improving high-frequency websites, has made the component search somewhat easier. And with the latest generation of component search tools from Mini-Circuits, the Yoni2 engine, designers can even select specific subbands and performance parameters within a component's total range of operation for that optimum match of component to application.

Rather than sorting though copies of data sheets, Yoni2 (Fig. 1) allows engineers to search through an enormous amount of actual data to find the best component for a particular requirement. In fact, the algorithms with which Yoni2 sorts through the data are so efficient that they represent the unique instance in which one of the functions of a high-frequency website is patent-pending.

According to Mini-Circuits' president Harvey Kaylie, the development of Yoni2 was spurred by an awareness of how customers were using the company's parts. In some cases, rather than simply selecting, for example, a double-balanced mixer with RF and intermediatefrequency (IF) ranges to translate a desired signal band, engineers were using broader-band mixers over narrower portions of their range to meet a required linearity specification, or conversion-loss level, or optimum local-oscillator (LO) drive level. " Sometimes you don't need the entire usable bandwidth of a component, but just a portion of it, especially where that segment of its operating range gives you better performance than you might get with a narrow-band solution," says Kaylie.

Constructing the Yoni2 database and search functions was not simply a matter of copying data-sheet files of compiling specifications from existing catalogues. When the Yoni2 search tool triggers on a user's input parameters, it begins a highspeed sort through actual measured data for each component in a category, attempting to match performance limits or a performance window to a customer's request. Collecting this amount of measured data, of course, is extremely time consuming and would have been impractical if not for a major investment on the part of Mini-Circuits in new RF/microwave test systems which include high-performance vector network analyzers and fast-switching synthesized signal sources. Kaylie notes, "We worked very closely with a major international supplier of RF and microwave test equipment, installing quite a few of these test stations in support of Yoni2. It required a cooperative effort to achieve the test performance levels we needed." Kaylie adds, "These are literally millions of points of test data that were compiled in a short time on our existing product lines. And this will be done for all new products—full characterization of performance under different conditions, including temperature, to allow engineers to search for components meeting very specific requirements."

Many companies offer product category searches or the capability of searching for a specific model number. The Yoni2 search tool allows uses to perform a search within a given product category based on their own specifications. How well does it work? During an evaluation of the firm's next-generation website, Yoni2 was used to find components for several typical applications including a microwave mixer.

Although Mini-Circuits is associated-with RF components, the firm also offers component beyond 10 GHz for microwave applications. In attempting to find a broadband microwave mixer for applications covering 4 to 12 GHz, Yoni2 was used with its mixer search request screen (Fig. 2) to search for a mixer that would provide no worse than 10 dB conversion loss and operate with LO drive level of +7 dBm. A word of caution when entering search data: Yoni2 is not all knowing, and upon entering LO drive level in its familiar +7 and +10 configurations (for +7 and +10 dBm), Yoni2 flagged the entry as incorrect (not a number) because of the "plus" sign. Once the plus sign was removed, the search engine quickly jumped to the next screen (Fig. 3) , indicating that a perfect match was not available but that the search would continue based on one or two priorities, such as conversion loss, LO-RF isolation, LO-IF isolation, IP3, VSWR, or none. By leaving the default setting of conversion loss, the search tool quickly found a model MCA1-12GL mixer with LO/RF range of 3.8 to 12.0 GHz and IF range of DC to 1.5 GHz (Fig. 4).

From the results screen of a mixer search, an operator can click on the model number to show a screen that offers a data sheet as well as choices to view graphs or view data (Fig. 5). It also shows details about the package, circuit layout, environmental ratings, even information about an evaluation board. Clicking on "View Graphs" brings up on-screen performance plots (Fig. 6) that include conversion loss, input IP3, LO-to-RF isolation, LO-to-IF isolation, and VSWR for the LO, RF, and IF ports.

Similar searches were performed using Yoni2 for a voltage-controlled oscillator (VCO), broadband amplifier, and bandpass filter. Each "Search Request" screen is different, customized for the particular component. During the VCO search, for example, the screen permits search parameters to be entered for oscillator frequency range, supply voltage, phase noise at four different offset frequencies (although only one or two of these entries need be completed for a successful search), minimum/maximumoutput power, minimum/maximumtuning sensitivity, and even harmonic levels.

Using simple search parameters of 1500 to 1600 MHz and phase noise of -86 dBc/Hz offset 1 kHz from the carrier and -140 dBc/Hz offset 1 MHz from the carrier, Yoni2 found a model ROSEDR5630 VCO. The search engine even shows the elapsed time of the search, in this case a mere 0.02 s. As with the mixer, a user can then save or print a data sheet and quickly view performance data or plots that include tuning linearity, harmonics, output power versus tuning voltage, frequency pushing, and phase noise. Additional information is provided about tape-and-reel packaging, housing dimensions, circuit-board mounting, and an evaluation board.

In the case of an amplifier, search parameters include package style, frequency range, minimum gain and isolation, minimum output power, and maximum noise figure. As with the other search mechanisms within Yoni2, a minimum number of these parameters need be entered for a search to be successful. For example, in performing a search by just entering the amplifier frequency range of 2 to 5000 MHz and minimum gain of 10 dB, Yoni2 came up with a model GALI-74 amplifier, although the listed frequency range on the "Search Results" page was DC to 1000 MHz. But clicking on the menu choice to view performance brought up several screens full of actual performance data from 1 to 8835 MHz, complete with measured S-parameters. Plots were also available for power gain, input and output return loss, and isolation. Such S-parameter data are invaluable for modeling commercial components in popular commercial circuit simulators, such as the Advanced Design System (ADS) software simulation suite from Agilent Technologies (www.agilent.com) and Ansoft Designer from Ansoft (www.ansoft.com). Having the actual measured S-parameter data (rather than general parameters) improves simulation accuracy and can reduce the time needed for achieving meaningful simulation results.

Finally, Yoni2 was used to track down a bandpass filter that could be used around a GPS signal at 1575 MHz. Entering a few simple parameters, such as the upper and lower limits of the passband and maximum passband insertion loss, and relaxing the packaging requirement by selecting the "Not Critical" choice, the Search Results screen shows four candidates. Interestingly, the search tool selected Engineering Development Models for these requirements, including the model VBFZ-EDR8448U SMA bandpass filter with a center frequency of 1600 MHz and passband loss of less than 2 dB. Information on the filter notes that it is a non-catalog model, although full information and pricing is available upon request. As with the other searched items, response plots of filter insertion loss and return loss were also available.

At present, Yoni2 supports searches across amplifiers, directional couplers, mixers, power splitters and combiners, RF transformers, VCOs, and filters. Even with the new test equipment, characterization of the company's many product lines takes time, and search capability must still be added for the firm's extensive lines of coaxial adapters, analog and digital attenuators, DC blocks, RF switches, terminations, and test cables. Eventually, all product lines will be supported by the powerful Yoni2 search tool. Mini-Circuits, P.O. Box 350166, Brooklyn, NY 11235-0003; (718) 934-4500, FAX: (718) 332-4661, Internet: www.minicircuits.com.