For the past 10 years, the automated synthesis of microwave devices has been growing more popular in computer-aided-engineering (CAE) applications. With access to information and various automated design algorithms and export models, for example, an engineer can quickly evaluate different antenna topologies. He or she can then choose an appropriate topology for the design task at hand. In a four-page application note titled “Design Flow for Base Station Antenna,”  AWR Corp. shows how software like its Antenna Magus product can be used to hasten early design stages. Such software also makes it easier to export specific designs into electronic-design-automation (EDA) tools.
The note uses a wide-area-network (WAN) base-station antenna as a design example. Here, the goal is to ensure adequate signal coverage for several homes in an area using just one base station. Typically, designers would consider various antenna topologies with which they are familiar and determine if one would be suitable. If not, they would begin an online product search and potentially reach out to antenna manufacturers with which they have partnered. With software like Antenna Magus, however, they could begin by simply considering a selection of antenna topologies—all of them familiar—and decide if one would be a good choice.
Such software serves as an information resource. It allows engineers to search for and explore a variety of options, get more information on them, and compare them. To help the designer derive antenna requirements from system specifications, utilities like a free-space path-loss calculator are included. In the example, the calculation shows that a transmit antenna with 18-dBi gain in the directions of required coverage is needed, given the requirement of -60-dBm power from a 16-dBi receive antenna at 1 km from a 5-mW transmitter. To provide the required coverage, a high-gain fan-shaped beam would be ideal. Using the keywords “fan beam” and “high gain,” the engineer can quickly access six technology options with performance information that can be easily compared.
The note closes with another example, which illustrates how today’s software tools allow an antenna design to be created and exported. The software performs some tasks automatically, such as calculating the effective dielectric constant of a two-layer dielectric and finding the correct feed spacing for a good match. The user specifies bottom-substrate height and top-substrate parameters and the antenna is rapidly designed. Such software options are very helpful for finding a first-order design in a rapid fashion, assessing its performance, and exporting parameterized models.
AWR Corp., 1960 E. Grand Ave., Ste. 430, El Segundo, CA 90245; (310) 726-3000, www.awrcorp.com .