Compact hybrid couplers having strong broadband coupling for base station antenna systems

A four-port radio-frequency (RF) hybrid coupler, comprising:

• a substrate;
• first and second primary traces on a first surface of the substrate;
• a first coupled trace on the first surface of the substrate, said first coupled trace having:
• (i) a first end configured to provide a first degree of RF coupling to a first end of the first primary trace when the RF hybrid coupler is active, and (ii) a second end configured to provide a third degree of RF coupling to a second end of the second primary trace when the RF hybrid coupler is active;
• a second coupled trace on the first surface of the substrate, said second coupled trace having:
• (i) a first end configured to provide a fourth degree of RF coupling to the first end of the second primary trace when the RF hybrid coupler is active, and (ii) a second end configured to provide a second degree of RF coupling to the second end of the first primary trace when the RF hybrid coupler is active;
• a first energy cancellation circuit comprising a first termination coupler having an input port electrically coupled to an end of the second coupled trace;
• and
• a second energy cancellation circuit comprising a second termination coupler having an input port electrically coupled to an end of the first coupled trace.

A four-port radio-frequency (RF) hybrid coupler, comprising:

• a substrate;
• a first primary trace on a first surface of the substrate, said first primary trace having first and second ends electrically coupled to first and second ports of the coupler, respectively;
• a second primary trace on the first surface of the substrate, said second primary trace having first and second ends electrically coupled to fourth and third ports of the coupler, respectively;
• a first coupled trace on the first surface of the substrate, said first coupled trace having:
• (i) a first end comprising a plurality of trace segments connected in series, which collectively provide a first degree of RF coupling to the first end of the first primary trace adjacent the first port when the coupler is active, and (ii) a second end comprising a plurality of trace segments connected in series, which collectively provide a third degree of RF coupling to the second end of the second primary trace adjacent the third port when the coupler is active, which is unequal to the first degree of RF coupling;
• and
• a second coupled trace on the first surface of the substrate, said second coupled trace having:
• (i) a first end comprising a plurality of trace segments connected in series, which collectively provide a fourth degree of RF coupling to the first end of the second primary trace adjacent the fourth port when the coupler is active, and (ii) a second end comprising a plurality of trace segments connected in series, which collectively provide a second degree of RF coupling to the second end of the first primary trace adjacent the second port when the coupler is active, which is unequal to the fourth degree of RF coupling.