Portable radio antenna

• US 4,138,681 A
• Filed: 08/29/1977
• Issued: 02/06/1979
• Est. Priority Date: 08/29/1977
• Status: Expired due to Term

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Davidson, Allen L., Durante, James M.
• Primary Examiner(s): Smith, Alfred E.
• Assistant Examiner(s): Barlow, Harry E.
• Application Number:
  US05/828,565
• Time in Patent Office: 526 Days
• Field of Search: 343/702, 343/825, 343/828, 343/829, 343/830, 343/831, 343/844, 343/846
• US Class Current: 343/702
• CPC Class Codes: H01Q 1/245 with means for shaping the antenna pattern, e.g. in order to protect user against rf exposure
• CPC Class Codes: H01Q 1/273 Adaptation for carrying or wearing by persons or animals

Abstract

An antenna for a hand-held radio transceiver includes first and second elements extending from the radio'"'"'s case. The first element is comprised of a pair of series coupled members having electrical lengths of one-half and one-quarter wavelength, respectively, with the free end of the second member being coupled to the transmitter output. The second element couples to the radio'"'"'s electrical ground and is configured to form a transmission line with the second member. The effective electrical length of the second element, including the influence of the elements parasitic coupling to the radio, is adjusted to be one-quarter wavelength.

The resulting antenna structure minimizes surface currents across the radio'"'"'s body, thereby substantially eliminating power loss caused by absorption in the user'"'"'s body.

Claims

1. A radio/antenna combination for operation on a wavelength λ

comprising;

a radio body including radio circuitry having first and second antenna connections; and

an antenna comprising;

a first radiating element, extending from said body, and being electrically coupled to said first antenna connection, said first radiating element having a predetermined electrical length; and

a second radiating element, extending from said body and being electrically coupled to said body and said second antenna connection, said second radiating element being in predetermined electrically mutually coupled relationship with said first radiating element and having a predetermined effective electrical length such that upon transmission by said radio the current distribution along the radio body is minimized.

2. The radio/antenna combination of claim 1 wherein the first and second radiating elements are of predetermined dimensions and are predeterminedly spaced such that said antenna exhibits a predetermined impedance at said antenna connections.

3. The radio/antenna combination of claim 1 wherein said first radiating element is comprised of first and second series, mutually coupled members, said first member having an electrical length of approximately mλ

/2, where m = 1, 2, 3 . . . , said second member having an electrical length of approximately nλ

/4, where n = 1, 3, 5 . . . , said first antenna connection being coupled to said second member.

4. The radio/antenna combination of claim 3 wherein:

said second radiating element is in a predetermined configuration with said second member to form a transmission line therewith, with the effective electrical length of said second radiating element, including the influence of said second member being electrically coupled to said radio body, being approximately nλ

/4, where n = 1, 3, 5 . . .

5. The radio/antenna combination of claim 4 wherein the first and second radiating elements are of predetermined dimensions and are predeterminedly spaced such that said antenna exhibits a predetermined impedance at said antenna connections.

6. A radio/antenna combination for operation on a wavelength λ

comprising;

a radio body including radio circuitry having first and second antenna connections; and

an antenna comprising;

a first radiating element comprising first and second series connected radiating members, said first member having an electrical length of approximately Mλ

/2, where m = 1, 2, 3 . . . , said second member having an electrical length of approximately nλ

/4, where n = 1, 3, 5 . . . , said first radiating element extending from said radio body with said first antenna connection being coupled to said second radiating member; and

a second radiating element, extending from said radio, and being electrically coupled to said radio body and to said second antenna connection, the second radiating element having a predetermined electrical length and being in predetermined configuration with said second member to form a transmission line therewith, such that upon transmission of energy by said radio over the antenna, current along said radio body is substantially inhibited.

7. The radio/antenna combination of claim 6 wherein the electrical length of said second radiating element, including the influence of said second radiating element being electrically coupled to the radio body, is approximately equal to the electrical length of said second member.

8. The radio/antenna combination of claim 6 wherein the first and second radiating elements are of predetermined dimensions and are predeterminedly spaced such that said antenna exhibits a predetermined impedance at said antenna connections.

9. A radio/transmitter antenna combination for operation on a wavelength λ

comprising;

a radio body including radio circuitry having first and second antenna connections; and

an antenna comprising;

a first radiating element comprising first and second series connected radiating members, said first member having an electrical length of approximately mλ

/2, where m = 1, 2, 3, . . . , said second member having an electrical length of approximately nλ

/4, where n = 1, 3, 5 . . . , said first radiating element extending from said radio body with said first antenna connection being coupled to said second radiating member; and

a second radiating element extending from said radio being electrically coupled to said radio body and to said second antenna connection, the second radiating element having an effective electrical length, including the influence of said second radiating element being electrically coupled to the radio body, approximately equal to said second member, with said second radiating element being in predetermined configuration with the second member to form an nλ

/4 length transmission line therewith.

10. The radio transmitter/antenna combination of claim 9 wherein the first and second radiating elements are of predetermined dimensions and are predeterminedly spaced such that said antenna exhibits a predetermined impedance at said antenna connections.