Frequency selective reflector

A frequency selective reflector for receiving and reflecting electromagnetic waves, comprising:

• an inner portion having a reflective surface which reflects electromagnetic waves having a first frequency and electromagnetic waves having a second frequency;
• and
• an outer portion having a reflective surface which will constructively reflect electromagnetic waves having the first frequency but which will non-constructively reflect electromagnetic waves having the second frequency,
• wherein the outer portion reflective surface includes elements which cancel electromagnetic waves having the second frequency,
• wherein said elements comprise corrugation recesses having dimensions to reflect electromagnetic waves having the second frequency substantially 180° out of phase with respect to reflections of the electromagnetic waves having the second frequency from adjacent surfaces of the outer portion to thereby cancel the reflection of electromagnetic waves having the second frequency from the outer portion.

A frequency selective reflector for receiving and reflecting electromagnetic waves, comprising:

• an inner portion having a reflective surface which reflects electromagnetic waves having a first frequency and electromagnetic waves having a second frequency;
• and
• an outer portion having a reflective surface which will constructively reflect electromagnetic waves having the first frequency but which will non-constructively reflect electromagnetic waves having the second frequency,
• wherein the outer portion reflective surface includes elements which cancel electromagnetic waves having the second frequency,
• wherein said elements comprise stripes formed of a material which will reflect electromagnetic waves having the second frequency substantially 180° out of phase with the reflection of electromagnetic waves having the second frequency from adjacent surfaces of the outer portion to thereby cancel the reflection of electromagnetic waves having the second frequency from the outer portion.

A frequency selective reflector for an electromagnetic antenna comprising:

• an inner portion having a reflective surface to reflect electromagnetic waves having first and second frequencies;
• and
• an outer portion having a reflective surface which will reflect electromagnetic waves having the first frequency in the same direction as the reflection direction of electromagnetic waves having the first frequency reflected from the inner portion, and which reflective surface prevents reflection of electromagnetic waves having the second frequency in the same direction as the direction of reflection of electromagnetic waves having the second frequency reflected from the inner surface,
• wherein the diameters of the inner and outer portions are selected so that the reflectors electrical size in terms of wavelengths will be substantially equalized for the first and second frequencies so that the beam widths of radiation patterns for the first and second frequencies will be substantially equalized.

A frequency selective reflector for an electromagnetic antenna comprising:

• an inner portion having a reflective surface to reflect electromagnetic waves having first and second frequencies;
• and
• an outer portion having a reflective surface which will reflect electromagnetic waves having the first frequency in the same direction as the reflection direction of electromagnetic waves having the first frequency reflected from the inner portion, and which prevents reflection of electromagnetic waves having the second frequency in the same direction as the direction of reflection of electromagnetic waves having the second frequency reflected from the inner surface,
• wherein the diameters of the inner and outer portions are selected so that the reflectors electrical size in terms of wavelengths will be substantially equalized for the first and second frequencies so that the beam widths of radiation patterns for the first and second frequencies will be substantially equalized,
• wherein the outer portion reflective surface includes elements which cancel the electromagnetic waves of the second frequency to prevent reflection of the electromagnetic waves of the second frequency from the outer portion,
• wherein said elements comprise corrugation recesses having dimensions to reflect electromagnetic waves having the second frequency substantially 180° out of phase with respect to reflections of the electromagnetic waves having the second frequency from adjacent surfaces of the outer portion to thereby cancel the reflection of electromagnetic waves having the second frequency from the outer portion.

A frequency selective reflector for an electromagnetic antenna comprising:

• an inner portion having a reflective surface to reflect electromagnetic waves having first and second frequencies;
• and
• an outer portion having a reflective surface which will reflect electromagnetic waves having the first frequency in the same direction as the reflection direction of electromagnetic waves having the first frequency reflected from the inner portion, and which prevents reflection of electromagnetic waves having the second frequency in the same direction as the direction of reflection of electromagnetic waves having the second frequency reflected from the inner surface,
• wherein the diameters of the inner and outer portions are selected so that the reflectors electrical size in terms of wavelengths will be substantially equalized for the first and second frequencies so that the beam widths of radiation patterns for the first and second frequencies will be substantially equalized,
• wherein the outer portion reflective surface includes elements which cancel the electromagnetic waves of the second frequency to prevent reflection of the electromagnetic waves of the second frequency from the outer portion,
• wherein said elements comprise stripes formed of a material which will reflect electromagnetic waves having the second frequency substantially 180° out of phase with the reflection of electromagnetic waves having the second frequency from adjacent surfaces of the outer portion to thereby cancel the reflection of electromagnetic waves having the second frequency from the outer portion.

A substantially circular frequency selective reflector for receiving and reflecting electromagnetic waves having different frequencies to provide substantially equal beam widths for radiation patterns of the electromagnetic waves, comprising:

• an inner circular portion having a reflective surface which will reflect electromagnetic waves having a first frequency and a second frequency, wherein the first frequency is lower than the second frequency;
• and
• an outer circular portion substantially surrounding the inner circular portion, wherein the outer circular portion includes a corrugated surface to provide first and second reflective portions operating in conjunction with one another to reflect electromagnetic waves having the first frequency and to cancel electromagnetic waves having the second frequency,
• wherein the diameters of the inner and outer circular portions are selected so that the reflector's electrical size in terms of wavelengths will be substantially equalized for the first and second frequencies so that the beam widths of radiation patterns for the first and second frequencies will be substantially equalized.

A substantially circular frequency selective reflector for receiving and reflecting electromagnetic waves having different frequencies to provide substantially equal beam widths for radiation patterns of the electromagnetic waves, comprising:

• an inner circular portion having a reflective surface which will reflect electromagnetic waves having a first frequency and a second frequency, wherein the first frequency is lower than the second frequency;
• and
• an outer circular portion substantially surrounding the inner circular portion, wherein the outer circular portion includes a diffraction grating which will diffract electromagnetic waves having the first frequency in a direction to align with electromagnetic waves of the first frequency reflected from the inner portion, and which will divert electromagnetic waves of the second frequency in a direction different than the direction of electromagnetic waves of the second frequency reflected from the inner circular portion,
• wherein the diameters of the inner and outer circular portions are selected so that the reflector's electrical size in terms of wavelengths will be substantially equalized for the first and second frequencies so that the beam widths of radiation patterns for the first and second frequencies will be substantially equalized.