AWR Application Notes

AWR Software for the Design of MIMO and Phased Array Antenna Systems 2 www.cadence.com/go/awr Phased Array Design Flow A leading phased array design flow is available with Cadence ® AWR ® Visual System Simulator™ (VSS), the system-level simulator that operates within the Cadence AWR Design Environment ® platform. The simulator provides full system perfor- mance as a function of steered-beam direction, inclusive of the antenna design and the active and passive circuit elements used to implement the electronic beam steering. System components can be modeled in greater detail using Cadence AWR Microwave Office ® circuit simulation, inclusive of EM analysis for antenna design and passive device modeling using Cadence AWR AXIEM ® 3D planar and Analyst™ 3D finite-element method EM simulators. These tools are fully integrated into the AWR Design Environment, supporting seamless data sharing within the phased array hierarchy. Furthermore, individual antenna designs can be generated from performance specifications using the Cadence AWR AntSyn™ antenna synthesis and optimization module, with resulting geometries imported into Cadence AWR AXIEM or Analyst software for further EM analysis and optimization. Highlights of phased array analysis in AWR VSS software include: f Automate/manage the implementation of beamforming algorithms and determine phased array antenna configuration from a single input/output block f Accomplish array performance over a range of user-specified parameters such as power level and/or frequency. f Perform various link-budget analyses of the RF feed network, including measurements such as cascaded gain, noise figure (NF), output power (P1dB), gain-to-noise temperature (G/T), and more f Evaluate sensitivity to imperfections and hardware impairments via yield analysis f Perform end-to-end system simulations using a complete model of the phased array f Simulate changing array impedance as a function of beam angle to study the impact of impedance mismatch and gain compression on front-end amplifier performance Defining Phased Array Configurations Specifications for any phased array radar are driven by the platform requirements and the intended application. For example, weather observation, which has relied on radar since the earliest days of this technology, most commonly uses airborne surveillance radar to detect and provide timely warnings of severe storms with hazardous winds and damaging hail. The weather surveillance radars are allocated to the S (~ 10cm wavelength), C (~ 5cm wavelength), and X (~ 3cm wavelength) frequency bands. While the shorter wavelength radars provide the benefit of a smaller antenna size, their radiated signals are significantly affected by atmospheric attenuation. Requirements for 10cm wavelength (S-band) weather surveillance radars, based on years of experience with the national network of non-Doppler radars (WSR-57), are shown in Table 1 1 . Table 1: Requirements for 10cm wavelength weather surveillance radars 2 1.1. Surveillance 1.1.1 Range: 460 km 1.1.2 Time: < 5 minutes 1.1.3 Volumetric coverage: hemispherical 1.2. SNR: > 10 dB, for Z. 15 dBZ at r = 230 km 1.3. Angular resolution: ≤1 o 1.4. Range sample interval Δr 1.4.1 for reflectivity estimates: Δr < 1 km; 0 < r <230 km Δr < 2 km; r < 460 km 1.4.2 for velocity and spectrum width estimates (r < 230 km): Δr = 250 m 1.5. Estimate accuracy: 1.5.1 reflectivity: ≤1 dB 1.5.2 velocity: ≤1 m s -1 ; SNR> 8 dB; σ v = 4 m s -1 1.5.3 spectrum width: ≤1 m s -1 ; SNR>10 dB; σ v = 4 m s -1

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