Miniature 180 degree hybrid coupler

A 180° hybrid coupler, comprising:

• a first impedance network and a second impedance network, each configured to function as a balun, said first impedance network and said second impedance network each having a first characteristic impedance;
• a first and second input node, and a first and second output node;
• said first and second input node of said first impedance network respectively connected to said first and second input node of said second impedance network;
• a third impedance network and a fourth impedance network, each configured to function as a balun, said third and fourth impedance network each having a second characteristic impedance, a first and second input node, and a first and second output node;
• a first output node of said first impedance network connected to said first input node of said third impedance network, and said second output node of said first impedance network connected to said second input node of said fourth impedance network;
• said first output node of said second impedance network connected to a first input node of said fourth impedance network, and said second output node of said second impedance network connected to said second input node of said third impedance network;
• a first resistor connected between said second output nodes of said first impedance network and said second impedance network;
• a second resistor connected between said first output nodes of said first impedance network and said second impedance network;
• wherein said first, second, third, and fourth impedance networks are transmission line transformers comprised of coplanar stripline;
• wherein said transmission line transformers are configured to produce a first output signal from said third impedance transformer, which is approximately 180 degrees out of phase relative to a second output signal from said fourth impedance transformer, when an input signal is applied to said first and second input nodes of said first and second impedance transformers.

A 180° hybrid coupler, comprising:

• a first impedance network and a second impedance network, each configured as a balun and having a first characteristic impedance;
• a first and second input node, and a first and second output node;
• said first and second input node of said first impedance network respectively connected to said first and second input node of said second impedance network;
• a third impedance network and a fourth impedance network, each configured as a balun and having a second characteristic impedance, a first and second input node, and a first and second output node;
• a first output node of said first impedance network connected to said first input node of said third impedance network, and said second output node of said first impedance network connected to said second input node of said fourth impedance network;
• said first output node of said second impedance network connected to a first input node of said fourth impedance network, and said second output node of said second impedance network connected to said second input node of said third impedance network;
• a first resistor connected between said second output nodes of said first impedance network and said second impedance network;
• a second resistor connected between said first output nodes of said first impedance network and said second impedance network;
• wherein said first, second, third, and fourth impedance networks are configured to produce a first output signal from said third impedance network which is approximately 180 degrees out of phase relative to a second output signal from said fourth impedance network when an input signal is applied to said first and second impedance networks.