A balun circuit includes a dielectric substrate having planar opposing surfaces: a groundplane conductor layer disposed on a first opposing surface; an interlayer conductor layer disposed on a second opposing surface and including first and second electrically isolated conducting strips, with a balance point gap between first ends thereof, and second ends thereof being short-circuited; an interlayer dielectric layer having substantially planar opposing surfaces, with a first opposing surface thereof being disposed over the interlayer conductor layer; and a top conductor layer disposed over a second opposing surface of the interlayer dielectric layer and including a third conducting strip overlying the first and second conducting strips, one end of the third conducting strip providing an unbalanced port terminal and another end of the third conducting strip being open-circuited. The third conducting strip includes a first and a second set of series-connected line sections each having diverse impedances which are a mirror opposite of each other relative to a center plane of the balun circuit. The first and second conducting strip have impedances which are a mirror opposite of each other relative to the center plane of the balun circuit. The impedances of the first and second conducting strips can be diverse impedances. Phase and amplitude balance at the balance point gap is achieved by the mirror opposite relationship of the impedances of the first and second set of line sections and the mirror opposite relationship of the impedances of the first and second conducting strips.

Miniaturized balun transformer

A chip-type low-temperature co-fired ceramic (LTCC) multilayer ceramic (MLC) balun is presented in this paper. This balun is designed using the stepped impedance method. It uses a multilayer structure, meander lines, and multisection coupled lines. The use of multisection couple lines that have various characteristic impedance ratios can shrink the length of a quarter-wavelength coupled-transmission line and makes it very easy to match various impedances of balanced output. The proposed chip-type balun operates over a bandwidth of 2.25-2.65 GHz. The in-band phase and amplitude balances are excellent because of the symmetric structure and transmission-line trimming section. Measured results of the chip-type LTCC-MLC balun match well with the computer simulation.

Chip-type LTCC-MLC baluns using the stepped impedance method

A chip-type low-temperature co-fired ceramic (LTCC) multilayer ceramic (MLC) balun is presented in this paper. This balun is designed using the stepped impedance method. It uses a multilayer structure, meander lines, and multisection coupled lines. The use of multisection couple lines that have various characteristic impedance ratios can shrink the length of a quarter-wavelength coupled-transmission line and makes it very easy to match various impedances of balanced output. The proposed chip-type balun operates over a bandwidth of 2.25-2.65 GHz. The in-band phase and amplitude balances are excellent because of the symmetric structure and transmission-line trimming section. Measured results of the chip-type LTCC-MLC balun match well with the computer simulation. Index Terms—Balun, chip-type component, LTCC, MLC, mul- tisection coupled lines, stepped impedance method.

http://ieeexplore.ieee.org/iel5/22/20945/00971619.pdf

Chip-Type LTCC-MLC Baluns Using the Stepped

A miniaturized wideband balun circuit is disclosed which includes a first dielectric substrate having substantially planar opposing surfaces; first and second conducting strips disposed on a first one of the opposing surfaces of the first dielectric substrate and each having a first terminal and a second terminal; a second dielectric substrate having substantially planar opposing surfaces, with a first one of the opposing surfaces of the second dielectric substrate being disposed over the first and second conducting strips; third and fourth conducting strips disposed on a second one of the opposing surfaces of the second dielectric layer and each having a first terminal and a second terminal The first and second conducting strips overlie the third and fourth conducting strips, respectively The first and second terminals of the first conducting strip, the first terminal of the second conducting strip and the second terminal of the fourth conducting strip are electrically grounded The first terminal of the third and fourth conducting strips are connected to an unbalanced port The second terminal of the third conducting strip is connected to a first balanced port, and the second terminal of the second conducting strip is connected to a second balanced port

Miniaturized broadband balun transformer having broadside coupled lines

An integrated power amplifier can include a carrier amplifier, where the carrier amplifier is connected to a first quarter wave transformer at the input of the carrier amplifier. In addition, the power amplifier can further include at least one peaking amplifier connected in parallel with the carrier amplifier; a first differential combining structure, where the first combining structure includes a first plurality of quarter wave transformers that are configured to combine respective first differential outputs of the carrier amplifier in phase to generate a first single-ended output signal, and a second differential combining structure, where the second combining structures includes a second plurality of quarter wave transformers that are configured to combine respective second differential outputs of the at least one peaking amplifier in phase to generate a second single-ended output signal, where the first single-ended output signal and the second single-ended output signal are combinable in-phase to provide an overall output.

Integrated power amplifiers for use in wireless communication devices

A balun, which does not use magnetic coupling and is easily integrated in MMICs, is formed of lumped parameter inductive and capacitive circuit elements. In one embodiment, a termination circuit is utilized to prevent reflections of common mode signals.

Lumped parameter balun

A circuit for simultaneously mixing two input signals and providing an output signal at double the frequency of one of the input signals includes a push-push doubler formed of dual-input mixing elements. Each input signal is coupled to the doubler/mixer through a phase-inverter to provide odd-mode input signal components.

Thomas R. Apel

Papers

Lumped parameter balun

Circuit for simultaneous frequency doubler and mixer