Jim RuffAntennas & Feeds PDR 2/12/02 1 Antennas & Feeds Mechanical Design Feed Cone Feed Mounting Horn Fabrication.

Jim Ruff Antennas & Feeds PDR2/12/02

1

Antennas & FeedsMechanical Design

Feed Cone

Feed Mounting

Horn Fabrication

Jim Ruff Antennas & Feeds PDR2/12/02

2

Feed Cone

• Why?– More Frequencies– RFI Containment– Reduced clutter at antenna vertex

• How?– Similar to existing K/Q segments– Monolithic

Jim Ruff Antennas & Feeds PDR2/12/02

3

Feed Circle

Jim Ruff Antennas & Feeds PDR2/12/02

4

EVLA Feed Cone

The L-Band horn is not contained in the feed cone.

Jim Ruff Antennas & Feeds PDR2/12/02

5

Feed Cone

Jim Ruff Antennas & Feeds PDR2/12/02

6

Feed Cone

• Unresolved Questions– Aluminum or Polycarbonate core?

• Aluminum cores are stiffer

• Polycarbonate cores are better thermally

– Service Access• Receiver heights vary greatly

• Space will be at a premium

Jim Ruff Antennas & Feeds PDR2/12/02

7

Feed Mounting

• Features:– Based on VLA X-Band– Continuous metal-to-metal for RFI containment– Simple horn installation and alignment– Convenient receiver swapping

• Which Bands?– S? C X Ku K? Ka? Q?

Jim Ruff Antennas & Feeds PDR2/12/02

8

Jim Ruff Antennas & Feeds PDR2/12/02

9

Feed Mounting

Jim Ruff Antennas & Feeds PDR2/12/02

10

Feed Mounting

Jim Ruff Antennas & Feeds PDR2/12/02

11

Feed Mounting

Jim Ruff Antennas & Feeds PDR2/12/02

12

Horn Fabrication

• Laminated Horns (L, S and C)– Similar to VLBA L-Band horns– Reduce weight and simplify construction– Tooling

Jim Ruff Antennas & Feeds PDR2/12/02

13

Laminated Horns

Jim Ruff Antennas & Feeds PDR2/12/02

14

Laminated Horns

Jim Ruff Antennas & Feeds PDR2/12/02

15

Ring Loaded Horns

• A Proposal for Ring Loaded Horns– Simplify assembly– Simplify receiver mounting– Improve flange mate-up reliability– Reduce manufacturing cost

Jim Ruff Antennas & Feeds PDR2/12/02

16

Ring Loaded Horns