Multi-Beam RF Aperture Using Multiplierless FFT Approximation

Abstract

Multiple independent radio frequency (RF) beams find applications in communications, radio astronomy, radar, and microwave imaging. An $N$-point FFT applied spatially across an array of receiver antennas provides $N$-independent RF beams at $\frac{N}{2}{\log }_{2}N$ multiplier complexity. Here, a low-complexity multiplierless approximation for the 8-point FFT is presented for RF beamforming, using only 26 additions. The algorithm provides eight beams that closely resemble the antenna array patterns of the traditional FFT-based beamformer albeit without using multipliers. The proposed FFT-like algorithm is useful for low-power RF multi-beam receivers; being synthesized in 45 nm CMOS technology at 1.1 V supply, and verified on-chip using a Xilinx Virtex-6 Lx240T FPGA device. The CMOS simulation and FPGA implementation indicate bandwidths of 588 MHz and 369 MHz, respectively, for each of the independent receive-mode RF beams.

8 pages, 3 figures, 2 tables, sfg corrected

Cited by in corpus (6)

• Fast Radix-32 Approximate DFTs for 1024-Beam Digital RF Beamforming
• Towards a Low-SWaP 1024-beam Digital Array: A 32-beam Sub-system at 5.8 GHz
• Multi-beam 4 GHz Microwave Apertures Using Current-Mode DFT Approximation on 65 nm CMOS
• Efficient and Self-Recursive Delay Vandermonde Algorithm for Multi-Beam Antenna Arrays
• Low-complexity Three-dimensional Discrete Hartley Transform Approximations for Medical Image Compression
• Multiplierless DFT Approximation Based on the Prime Factor Algorithm