Broadband antenna and processes for manufacturing such an antenna
The present invention relates to a broadband monopole antenna comprising a “cup”-shaped radiating element mounted on an earth plane forming support of annular shape. This antenna can be used in the field of portable television apparatuses.
1. Broadband monopole antenna, comprising a radiating element mounted on an earth plane forming support of annular shape, wherein the radiating element is constituted by a hollow element having a “cup” shape integral with the earth plane forming support, said radiating element and said support being made on the basis of a metallizable plastic or foam, the external profile of the “cup”-shaped radiating element being given by the following equations:
For
1.3
<
t
<
4.075
x
(
t
)
=
8
+
1.9
*
t
*
Cos
(
t
-
7
)
z
(
t
)
=
2.5
+
12.5
Sin
(
t
)
t
with t being a number varying between 1.3 and 4.075 and coordinates (x(t),z(t)) representing points along the profile.
2. Antenna according to claim 1 , wherein the earth plane forming support of annular shape consists of a circular annulus.
3. Antenna according to claim 2 , wherein the external end of the annulus is inwardly curved in such a way as to form a semi-toroidal element.
4. Process for manufacturing a broadband monopole antenna comprising radiating element constituted by a hollow element having a “cup” shape, said radiating element being mounted on an earth plane forming support, said process comprising a step of making the “cup”-shaped radiating element integral with the earth plane forming support by injection moulding of a plastic followed by a step of metallizing at least the exterior surface of the “cup”-shaped element and of the part forming earth plane, the profile of the “cup” shaped element being given by the following equations:
For
1.3
<
t
<
4.075
x
(
t
)
=
8
+
1.9
*
t
*
Cos
(
t
-
7
)
z
(
t
)
=
2.5
+
12.5
Sin
(
t
)
t
with t being a number varying between 1.3 and 4.075 and coordinates (x(t),z(t)) representing points along the profile.
5. Process according to claim 4 , wherein the metallization is achieved by vacuum spraying of the metal.
6. Process according to claim 4 , wherein the metallization is achieved by an electrochemical process.
7. Process for manufacturing a broadband monopole antenna comprising a radiating element constituted by a hollow element having a “cup” shape, said radiating element being mounted on an earth plane, comprising a step of making the “cup”-shaped radiating element integral with the earth plane forming support by machining a single block of metallizable foam followed by a step of metallizing at least the hollow surface of the “cup”-shaped element and of the part forming earth plane, the profile of the “cup” shaped element being given by the following equations:
For
1.3
<
t
<
4.075
x
(
t
)
=
8
+
1.9
*
t
*
Cos
(
t
-
7
)
z
(
t
)
=
2.5
+
12.5
Sin
(
t
)
t
with t being a number varying between 1.3 and 4.075 and coordinates (x(t),z(t)) representing points along the profile.
8. Process according to claim 7 , wherein the metallization is achieved by atomization of an electrically conducting paint.