8/12/2019 Antena tipo Lazo

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Bow Tie Antenna for 8GHz

Escuela Superior Politcnica de Chimborazo

Mayra Ortiz mayra_e_ortiz@yahoo.es

Marllory Cobos marllo9223@hotmail.com

Galo Hurtado galho9@hotmail.comDaniel Ripalda dripaldacarranza@yahoo.com

Katherine Gavilanez katherine2991gl@gmail.com

ResumenUsing antenna tie shaped funcionmiento for better anten-

na, increasing its bandwidth. is an antenna which functions to 8GHz.

working frequency will depend on the distance and angle that form

in Figure tie. This antenna is easy to fabricate and presents a very

efficient, making it well known. For efficient operation frequency must

engage the angle between the two plates that make up the loop, as

these measures qua plachas both width and length.

1. Introduction

The Bow Tie Antenna is a simple design that can be found in many

variations. While very inexpensive to build, this design is able to pull in

stations from 45 and 50 miles away.

In Figure 1, we have an antenna that is specified solely by the angle

between the two metal pieces, D. The antenna feed (where the radio

positive and negative terminals connect to the antenna) is at the center

of the antenna. Our antenna here is infinitely long in both directions, so

that wavelength never comes into the equation. As a result, this antennawould theoretically have an infinite bandwidth, because if it works at one

frequency (any frequency), it must work at ALL frequencies, because the

antenna looks the same at all wavelengths. This is a nice antenna.

fig.1: Loop Antenna Form

In terms of making a real antenna, we can take the simple approach

and just clip it after some distance and seeing what happens. The result

is the loop antenna (also known as a butterfly antenna, or a biconical

antenna).

The real bow tie antenna is fed with a coaxial cable. The coaxial

cable is soldered along the lower arm of the antenna, the purpose of this

is to minimize the impact of the antenna feed cable on the antenna.

This is similar to using a balun.the antenna, the purpose of this is to

minimize the impact of the antenna feed cable on the antenna. This is

similar to using a balun.

We see that the bow-tie antenna has much better bandwidth than a

thin-wire dipole antenna. In general, antennas with more volume have

wider bandwidth. More radiation modes can fit on the structure when

the current is less constrained.

Note that the fractional bandwidth of a thin wire dipole antenna is

about 8

2. Numerical and Experimental ResultsThe power antenna (where the positive and negative terminals are

connected radio antenna) is in the center of the antenna.

fig.2: Antenna simulation in HFSS

Our antenna of Figure 2 will operate in the frequency 8Ghz, which would

be a half-wavelength L = c/2/F where L = 10mm long. The real bow

tie antenna of Figure 1 is fed with a coaxial cable. The coaxial cable

is welded along the lower arm of the antenna - the purpose of this is

to minimize the impact of the power cord antenna The analysis will

be performed between 8 12 GHz. Therefore the minimum distance

between the air volume wall and the radiating aperture should be one

quarter wavelength at 8 GHz, or 0.25*(3e11/8e9) = 9.375mm. The

following dimensions round this up to 9.5mm spacing.

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fig.3 Frequency curve Of The Bow Tie Antenna

fig.4: Radiation pattern Of The Bow Tie Antenna

3. Conclusions

With this result we see that the antenna has much betterbandwidth a thin wire dipole antenna. In general, the more volume

antennas have broader bandwidth. More radiation modes can fit

into the structure when the current is less limited.

The bandwidth of these antennas is infinite because it will not

depend on the length of the antenna if your angle and it makes

you have more radiation in both directions.

The bow tie antenna is fed by a coaxial cable. The coaxial cable

is welded along the lower arm of the antenna for the purpose of

this is to minimize the impact of the antenna cord.

Referencias

[1] http://www.antenna-theory.com/antennas/wideband/bowtie.php,

[2] http://www.diytvantennas.com/bowtie.php,[3] Chuck Fung.Basic Antenna Theory and Application, March 15,

2011

fig.5: Impedances Of The Bow Tie Antenna