ANTENNA WITH LARGE CAPACITIVE TERMINATION AND LOW NOISE INPUT CIRCUIT

• US 3,827,053 A
• Filed: 02/28/1972
• Issued: 07/30/1974
• Est. Priority Date: 07/23/1970
• Status: Expired due to Term

• Current Assignee: Deceased Volkers, Edward N. Willie
• Original Assignee: Deceased Volkers, Edward N. Willie
• Inventors: Willie, Edward N., Volkers, deceased
• Primary Examiner(s): Lieberman, Eli
• Application Number:
  US05/229,992
• Time in Patent Office: 883 Days
• Field of Search: 343/701,828,899 325/373,376,377
• US Class Current: 343/701
• CPC Class Codes: H01Q 23/00 Antennas with active circuits or circuit elements integrated within them or attached to them
• CPC Class Codes: H01Q 9/36 with top loading

Abstract

An antenna having a short stem and a larger than normal capacitive termination to provide improved performance over antennas of the same effective electrical length, and an input circuit having a larger than normal total input resistance for obtaining improved signal-to-noise ratios by using the capacitive reactance of said antenna as a noise sink.

Claims

1. Radio receiver apparatus comprising:

an antenna comprising a stem, and a termination mounted on an end of said stem, the length of said stem being less than one eighth of the shortest wavelength at which the antenna is to be operated, and the maximum dimension of said termination being less than one eighth of the shortest wavelength at which the antenna is to be operated, the radiation capacity of said termination being at least one and one-half times that which would increase the effective electrical length of said antenna to 180 percent of the physical length of said stem; and

an input circuit comprising an amplifying device having a high inherent input impedance, said amplifying device having its input connected to said stem of said antenna and a bias resistance network connected to said input of said amplifying device to provide an appropriate bias level for said input of said amplifying device, the total resistance of said bias resistance network being less than the inherent input resistance of said amplifying device, the total input resistance of the combination of said amplifying device, and said bias resistance network being at least an order of magnitude greater than the capacitive reactance of said antenna whereby said capacitive reactance of said antenna acts as a sink for the inherent noise of said amplifying device.

2. The radio receiver apparatus of claim 1 wherein the total input resistance of the combination of said amplifying device and said bias resistance network is at least two orders of magnitude greater than the capacitive reactance of said antenna.

3. The radio receiver apparatus of claim 1 wherein said amplifying device comprises a field effect transistor.

4. The radio receiver apparatus of claim 1 further comprising a resistor in series between said stem of said antenna and said input of said amplifying device.