Highly efficient multi-port radiataor
A radiator is formed by forming a multitude of slot antennas adjacent one another such that the spacing between each pair of adjacent slot antennas is smaller than the wavelength of the signal being transmitted or received by the radiator. The radiator achieves high efficiency by reducing the excitation of substrate modes, and further achieves high output power radiation by combining power of multiple CMOS power amplifiers integrated in the radiator structure. Impedance matching to low-voltage CMOS power amplifiers is achieved through lowering the impedance at the radiator ports. Each output power stage may be implemented as a combination of several smaller output power stages operating in parallel, thereby allowing the combination to utilize an effective output device size commensurate with the impedance of the radiator.
1. A radiator comprising N slot antennas wherein a spacing between each pair of adjacent antennas is less than a wavelength of the electromagnetic signal being transmitted or received by the radiator, wherein N is an integer equal to or greater than 2, wherein each slot antenna is driven by M amplifiers at M different drive points positioned along a length of the slot antenna, wherein M is an integer equal to or greater than one, wherein the M drive points are distributed evenly along the length of the radiator, wherein each of the M amplifiers is a differential amplifier driving a different pair of adjacent slot antennas.
2. The radiator of claim 1 wherein the spacing is equal to or less than ¾ of the wavelength of the electromagnetic signals being transmitted or received by the radiator.
3. The radiator of claim 1 wherein the spacing is equal to or less than ½ of the wavelength of the electromagnetic signals being transmitted or received by the radiator.
4. The radiator of claim 1 wherein each of the M amplifiers is controlled by an associated switch adapted to place the amplifiers in one of a short, or open or active state at any given time.
5. The radiator of claim 4 wherein the N×M switches controlling the N×M amplifiers are controlled by a digital control block generating N×M digital signals each applied to a different one of the N×M switches.
6. The radiator of claim 5 wherein each differential amplifier comprises a pair of MOS transistors generating a pair of differential voltages applied to a pair of drive points positioned along a pair of associated adjacent slot antennas.
7. The radiator of claim 6 wherein each switch is adapted to control voltages applied to gate terminals of its associated MOS transistors.
8. A method of radiating an electromagnetic signal, the method comprising:
transmitting the electromagnetic signal from N slot antennas, wherein a spacing between each pair of adjacent antennas is less than a wavelength of the electromagnetic signal being transmitted, and wherein N is an integer equal to or greater than 2; and
driving each slot antenna by M amplifiers at M different drive points positioned along a length of the slot antenna, wherein M is an integer equal to or greater than one, wherein the M drive points are distributed evenly along the length of the radiator, wherein each of the M amplifiers is a differential amplifier driving a different pair of adjacent slot antennas.
9. The method of claim 8 wherein the spacing is equal to or less than ¾ of the wavelength of the electromagnetic signals being transmitted or received by the radiator.
10. The method of claim 8 wherein the spacing is equal to or less than ½ of the wavelength of the electromagnetic signals being transmitted or received by the radiator.
11. The method of claim 8 further comprising:
controlling each of the M amplifiers by an associated switch adapted to place the amplifiers in one of a short, open or active state at any given time.
12. The method of claim 11 further comprising:
controlling the N×M switches that control the N×M amplifiers by a digital control block generating N×M digital signals each applied to a different one of the N×M switches.
13. The method of claim 12 wherein each differential amplifier comprises a pair of MOS transistors generating a pair of differential voltages applied to a pair of drive points positioned along a pair of associated adjacent slot antennas.
14. The method of claim 13 wherein each switch is adapted to control voltages applied to gate terminal of its associated MOS transistors.