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Left Hand Circularly Polarized Helical Antenna Helix

ㅇ 종단방사 배열안테나 이득

D. Emerson, "The gain of the endfire array," ARRL Antenna Compendium Vol 5, 1996.

Gains of various antenna types against length

그림: 종단방사 배열 안테나 이득. HW = Hansen-Woodyard 배열

Gains of various antenna designs against number of elements

그림: 종단방사 배열 안테나 이득.

Helix gain: Kraus, King & Wong, NEC and Lee & Wong

그림: 나선 안테나 이득. LW = Leong and Wong theory, NEC = modelling, KW = King and Wong measurments, K = Kraus formula [Emerson(1995)]

Optimume Design: D. Emerson, "The gain of the axial-mode helix antenna", ARRL Antenna Compendium Volumr 4, 1995.

Gain of helices of different length, as function of diameter

Max. gain vs. length, and diameter for max. gain against length

그림: Aomway, 5.8GHz, 7-turn, 11dBic

그림: 5.8GHz, 8-turn, 12.2dBic, D70mm, H95mm

그림: 5.8GHz

그림: Q5X Shure HA-8089 460-900MHz, 50Ω, 14dBi, F/B 30dB, 57°, polycarbonate

Taco H-124, 240-320MHz, 12-turn, 50Ω, N(f), 500W, D145cm, H394cm, 16dBic, 33°, X-pol -20dB

Taco H-105, 300-520MHz SATCOM antenna

(a) Gain: 10dB/div, (b) Axial ratio: 0.2(linear)/div (minimum 1 the outermost circle)

AO-40, 2.4GHz, D60cm, F/D 0.39,

Helix: wire d 2.5mm, helix D 34.5mm, pitch angle 14°, ground plane D 30mm, NEC simulation, input impeance 98-j34Ω, 78-Ω quarter-wave transformer, input RG-213 cable

Backfire helical antenna

Nakano, "Backfire radiation from a monofilar helix with a small ground plane," IEEE T-AP, 36(10), 1988.

Nakano, "Generation of a circularly polarised conical beam from backfire helical antennas," Proc ICAP, 1991.

Johnson, "A backfire helical feed," IEEE T-AP, 32(10), 1984.

Yamaguchi, "Improvement of front-to-back ratio of backfire helical antenna," IEEE AP-S Symp Dig, 1992.

S-band Dish S-band Dish Feed S-band Helix Reflector

AMSAT: Parabolic dish, 20dBc, D585mm, F 194mm; Helix: 2.25 turn, wire dia 3.3mm, turn spacing 28mm, phase center in the middile of the helix, matching section 1/4 turn T0.2mm W6mm brass strip, Hstart 1.2mm, Hend 3.0mm; Feed and reflector support boom: 12.5mm square AL tube