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VHF ANTENNA FOR AVIONICS USING FR4

SUBMITTED BY,

RAHUL V RS1 M TECH CEROLL NO : 19

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OBJECTIVE

A new broadband antenna with very low profile is proposed.

Height is reduced to 0.03*the wavelength of lowest frequency.

The design consists of a top loaded monopole antenna and an inductive loading.

Wideband characteristics is achieved by the two resonance frequencies.

prototype – Bandwidth of 17% for VSWR smaller than 3.

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INTRODUCTION• That part of a

transmitting and receiving system that is designed to radiate or receive electromagnetic waves.

IEEE DEFENITION:

• Antenna impedance.

• Directivity.• Radiation pattern.• Electrical length

of antenna.

RECIPROCITY:

PARAMETERS:

Radiation pattern.

Power density.

Radiation intensity.

Directivity.

Gain.

Efficiency.

Bandwidth.

Radiation resistance.

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WDS MONOPOLE ANTENNA

• Ref:[2] Z. Zhi-Ya, F. Guang, W. Wei-Jun, L. Juan, and G. Shu-Xi, “A wideband dual-sleeve monopole antenna for indoor base station application,”

A wideband monopole antenna with dual-sleeve structure is proposed.

Operating bandwidth -137% ranging from 730 to 3880 MHz , VSWR ≤ 2.

Circular patch is shorted to the ground plane through four shorting probes.

Size reduction is achieved by the top loading of the circular patch.

0.07*λ, λ-free space wavelengths of low operating frequency.

Used in GSM 900,DCS1800,PCS 1900,UMTS,WLAN(IEEE 802.11b)

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BOR-SPR ANTENNA

Conducting body of revolution and a parasitic ring

shorted to a finite sized ground plate.

First, a slot is cut into the

patch.

Second, shorted parasitic

conducting pins are added to the periphery of the above antenna.VSWR

Bandwidth – 28%.

Replace inner feed region

with a conducting

BOR.

Height – 0.07* λ.

Ref:[3] H. Nakano, H. Iwaoka, K. Morishita, and J. Yamauchi, “A widebandlow-profile antenna composed of a conducting body of revolution and a shorted parasitic ring,”

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WBM PATCH ANTENNA

Ref:[4] R. Jeen-Sheen, Y. Shih-Huang, and W. Kin-Lu, “A wide-band monopolar plate-patch antenna,”

Planar rectangular monopole top loaded with a shorted square or circular patch.

Less than 10%

Square patch- thickness 0.8 mm.

Distance between patch and antenna ground is h( total antenna height is h+0.8)

Another structure with circular patch is studied.

Bandwidth increased- two ground plates are near to the edges.

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WIBOC ANTENNA

Two metallic plates:• upper-elliptical and lower -

rectangular.

Operating frequency- 30 – 3000 MHz.

Optimized height of the prototype – 343 mm.

The gain of the antenna is stable over the measured bandwidth.

Size reduction is not affect on:• Radiation pattern and Gain.

Ref:[5] S. Palud, F. Colombel, M. Himdi, and C. L. Meins, “Wideband omni directional and compact antenna for VHF/UHF band

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UWB-CSLA

Ref:[6] A. Elsherbini and K. Sarabandi, “Very low-profile top-loaded UWB coupled sectorial loops antenna,”

Based on CSLA.

Antenna height – 0.053*λ.

Easy and cost effective(PCB fabrication)

VSWR<2 over 0.9-6 GHz.

30-mil Rogers RO4003 substrate(fed using a std SMA coaxial cable).

Antenna size 0.05λ×0.36λ×0.36λ.

Low frequency radar and military applications.

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ANTENNA DESIGNInductive loading:

Reduce the antenna height.

Create a circular groove.

Shorting pin

loading:

Increase the bandwidth.

Bandwidth depends on

the pins.

Antenna design for avionics

application:

VHF communic

ation system-

116 to 138 MHz.

VSWR < 3.

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INDUCTIVE LOADING

Add a lumbed inductance.

Antenna bandwidth also increases.

The circular groove acts as a annular slot antenna and contributes to radiation.

Stub is realised in horizontal direction- volume is reduced.

Ls and Cs – Resonance frequency fs.

Parallel RLC – Resonance frequency fp.

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LENGTH OF SHORTED TRANSMISSION LINE

Most sensitive parameter- length of shorted

transmission line, lm.

Thickness of the wall, t, was varied within a

few millimetres.

Wm was kept constant.

Reduction of t – increase in fp.

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SHORTING PIN LOADING

Change the non-radiating

series resonance

to a radiating parallel

resonance

Shorting pins are

incorporated in the antenna.

Lower the resonance frequency

, fs.

Total size of the

antenna remain small.

Resonance frequency and input impedance:• Number

of pins.• Radius of

the pins.• Distance

between them.

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ANTENNA DESIGN[ AVIONICS ]

Diameter 30.25mm, height 8mm was assumed for the antenna volume.

Radius of the pins and

thickness of the plates kept constant.

Global optimization

based on generic algorithm was

run.

The result is locally optimized

with a quasi-Newton

algorithm.

2 configurations;• - No pins, middle

plate is present.• - no middle plate,

pins are present.

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INDEPENDENT BEHAVIOR OF RESONANCES

The currents on the shorting pins and feed pin are compared.

Simulated with 4 ports : three 50 Ω shorting pin and one coaxial feeding.

Relationship between current and voltage is [V]=[Z][I].

V1=1v, voltage at the feed port, V2=V3=V4=0v, voltage at the pins.

Using these voltages [I]can be calculated.

The Ipin/I1 was calculated.

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EXPERIMENTS AND RESULTS

Top plate – W/2 =30.25mm.

Middle plate Wm/2 =26mm.

Ground plane – single layer

FR4.50 Ω coaxial

cable.

2 mm above the ground

plane.

Outer conductor

radius-1.098mmInner

conductorradius- 0.255 mm.

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GAIN COMPARISON04/15/2023

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CONCLUSION

• From 1.16 – 1.38 GHz.

• Centre frequency – 1.26GHz.

Height is reduced to

0.03λ.

A new method of inductive loading is

introduced.

This method is useful in both wideband an narrowband

antennas.

Impedance bandwidth of

17% :

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REFERENCE• [1] Lida Akhoondzadeh-Asl, Jonathan Hill, Jean-Jacques Laurin, andMathieu

Riel” Novel Low Profile Wideband Monopole Antenna for Avionics Applications” ieee transactions on antennas and propagation, vol. 61,pp.5766-5770 NO. 11, NOVEMBER 2013

• [2] Z. Zhi-Ya, F. Guang, W. Wei-Jun, L. Juan, and G. Shu-Xi, “A wideband dual-sleeve monopole antenna for indoor base station application,”IEEE Antennas Wireless Propag. Lett., vol. 10, pp. 45–48, 2011.

• [3] H. Nakano, H. Iwaoka, K. Morishita, and J. Yamauchi, “A widebandlow-profile antenna composed of a conducting body of revolution and a shorted parasitic ring,” IEEE Trans. Antennas Propag., vol. 56, pp. 1187–1192, 2008.

• [4] R. Jeen-Sheen, Y. Shih-Huang, and W. Kin-Lu, “A wide-band monopolar plate-patch antenna,” IEEE Trans. Antennas Propag., vol. 50, pp. 1328–1330, 2002.

• [5] S. Palud, F. Colombel, M. Himdi, and C. L. Meins, “Wideband omnidirectional and compact antenna for VHF/UHF band,” IEEE Antennas Wireless Propag. Lett., vol. 10, pp. 3–6, 2011.

• [6] A. Elsherbini and K. Sarabandi, “Very low-profile top-loaded UWB coupled sectorial loops antenna,” IEEE Antennas Wireless Propag. Lett., vol. 10, pp. 800–803, 2011.

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