Novel corrugated horn antenna technology with stripline feeding
Fig. 1: Assembly of the PCB stack, the sink eroded taper and the stacked corrugated feedhorn bolted together.
Fig. 2: Layout of the stripline-to-waveguide transition for W-band.
Fig. 3: Cross-sectional view of the corrugated horn antenna with stacked platelets and the sink eroded WR-10 to circular taper.
Fig. 4: Comparison of simulated and measured data for the stripline-to-waveguide transition combined with the horn antenna.
In various applications, the feeding of horn antennas from a printed circuit board (PCB) in the millimeter wave range is decisive for implementation, e.g., in space applications. Critical parameters such as weight and volume need to be minimized. To address this, we have developed two innovations: a stripline-to-waveguide transition based on PCB technology and a corrugated horn antenna based on platelet technology (Fig. 1). When combined, they can be used for compact transmitter and receiver assemblies.
The stripline-to-waveguide transition based on PCB technology consists of three metal layers separated by two dielectric layers (Fig. 2). Layer 1 (red) forms the WR-10 waveguide opening (2.54 mm × 1.27 mm). Layer 2 (blue) contains a 100 µm wide probe within the polyimide, extending 550 µm orthogonally into the waveguide’s H-plane. Simulations suggest using an elliptical cut-out in this layer to minimize reflections. Layer 3 (pink) has a reduced opening size of 1.13 mm in the E-plane to improve impedance matching.
The corrugated horn antenna is realized by stacking layers of laser-cut aluminum alloy sheets with different thicknesses. This method alleviates the need for split-block manufacturing and uses cost-effective materials, making it perfect for rapid prototyping. To secure the plates, a taper is sink-eroded from an aluminum block, which forms the transition from the rectangular WR-10 waveguide to the round opening of the horn antenna (Fig. 3).
The stripline-to-waveguide transition and the corrugated horn antenna are designed for full W-band operation, but are scalable to lower and higher frequencies. The limits are set by the PCB manufacturer and the laser/EDM (electrical discharge machining) used for the antenna and its taper.
Our measurements show a reflection of around -10 dB with the overall structure and good agreement with the simulations (Fig. 4). This enables simulations to accurately predict real-world behavior, ensuring the scalability and adaptability of the structure for different frequencies.
The developments were realized as part of the MIMIRAWEII project in cooperation with the Goethe University Frankfurt, Germany and received financial support from the German Aerospace Agency DLR under contract no. 50RA1910 (2021 - 2024).
Publication
S. Nozinic, A. Rämer, E. Dischke, T. Flisgen, W. Heinrich, V. Krozer, “Layering it All: Stripline-to-Waveguide Transitions for Corrugated Horns at W-band”, European Microwave Conference 2024 (accepted for publication).