An antenna oscillator unit includes a radiator and a balun support. The radiator is fixed to the balun support and includes a plurality of low-frequency oscillator arms circumferentially distributed along the balun support. Each of the low-frequency oscillator arms includes two radiating sections connected to each other and a connecting section connecting the two radiating sections to form a closed loop. The two radiating sections are substantially perpendicular to each other. The antenna oscillator unit of some embodiments can avoid mutual coupling of signals from the antenna oscillator unit and an adjacent high-frequency oscillator and can improve the capability to radiate electromagnetic signals.

Impedance matching circuits, impedance matching elements, and radio communication circuits are provided in this disclosure. The impedance matching circuit may include a first impedance matching element which is configured to radio communication circuit may include a modulator configured to receive an unbalanced input signal from a first input, and couple the unbalanced input signal to a first output to match an impedance of the first output to a first impedance. It may further include a second impedance matching element coupled to the first input to receive the unbalanced input signal, the second impedance matching element configured to couple the unbalanced input signal to a second output to match an impedance of the second output to a second impedance. A terminal of the first output and a terminal of the second output may be coupled to provide a balanced output signal, and the coupling may match an output impedance of the impedance matching circuit based on the first impedance and the second impedance.

Techniques are provided for a broadband microwave/millimeter-wave balanced-to-unbalanced transformer (balun). A balun implementing the techniques according to an embodiment includes a first impedance matching network configured to reduce insertion and return losses of a single-ended signal at a first port of the balun. The balun also includes a first planar bifilar coupled transmission line coupled to the first impedance matching network and configured to transform the single-ended signal into a differential signal. The balun further includes a second planar bifilar coupled transmission line coupled to the first bifilar coupled transmission line and configured to compensate for amplitude and phase imbalance induced on the differential signal by the first bifilar coupled transmission line. The balun further includes a second impedance matching network coupled to both planar bifilar coupled transmission lines and configured to reduce insertion and return losses of the differential signal at second and third ports of the balun.

Transitional elements to offset a capacitive impedance in a transmission line are disclosed. Described are various examples of transitional elements in a multilayer substrate that introduce a transitional reactance to cancel the transmission line capacitive effects. The transitional elements reduce insertion loss.

Disclosed is an antenna including a radiating element, a co-planar ground plane element and a transmission line extending across at least a portion of the radiating element and the ground plane element. The transmission line includes a dielectric layer. The dielectric layer has a portion of a first major surface adjacent to the ground plane and a second major surface opposite and separated from the first surface. A shield is formed on the second major surface. At least one via extends through the dielectric layer to connect the shield to the ground plane. A feed line extends longitudinally through the dielectric layer from a feed point at a proximal end of the transmission line towards a distal end of the transmission line, the feed line being shielded along a portion of its length extending across the ground plane element by the shield with the distal end of the transmission line lying in register with the radiating element and coupling the feed line to the radiating element.

A balun includes an unbalanced terminal; balanced terminals; first and second main lines; and first and second sub-lines. The first main line has an end connected to the unbalanced terminal. The second main line has an end connected to the first main line and an end that is open. Each of the first and the second sub-lines is connected between the balanced terminal and a reference potential, respectively. The second sub-line includes a first partial line connected to the balanced terminal, and a second partial line connected between the first partial line and the reference potential. The second main line includes a third partial line connected to the first main line, and a fourth partial line connected to the third partial line. The distance between the first partial line and the third partial line is shorter than the distance between the second partial line and the fourth partial line.

A balun includes: an unbalanced terminal; a first and a second balanced terminals; a first and a second main lines; a first and a second sub-lines; and a first line. The first main line has a first end connected to the unbalanced terminal. The second main line has a first end connected to a second end of the first main line, and a second end that is open. The first sub-line is connected between the first balanced terminal and a reference potential, and is coupled to the first main line. The second sub-line is connected between the second balanced terminal and the reference potential, and is coupled to the second main line. The first line has a first end connected to the midpoint of the first sub-line, and a second end that is open. The first line is coupled to the first main line and the first sub-line.

A balun includes: an unbalanced terminal; a first and a second balanced terminals; a first and a second main lines; a first and a second sub-lines; and a first line. The first main line has a first end connected to the unbalanced terminal. The second main line has a first end connected to a second end of the first main line, and a second end that is open. The first sub-line is connected between the first balanced terminal and a reference potential, and is coupled to the first main line. The second sub-line is connected between the second balanced terminal and the reference potential, and is coupled to the second main line. The first line has a first end connected to the midpoint of the first sub-line, and a second end that is open. The first line is coupled to the first main line and the first sub-line.

This document describes techniques, apparatuses, and systems utilizing a high-isolation transition design for differential signal ports. A differential input transition structure includes a first layer and a second layer made of a conductive metal and a substrate positioned between the first and second layers. The second layer includes a first section that electrically connects to a single-ended signal contact point and to a first contact point of a differential signal port. The first section includes a first stub based on an input impedance of the single-ended signal contact point and a second stub based on a differential input impedance associated with the differential signal port. The second layer includes a second section that electrically connects to a second contact point of the differential signal port and to the first layer through a via housed in a pad. The second section includes a third stub associated with the differential input impedance.

This document describes techniques, apparatuses, and systems utilizing a high-isolation transition design for differential signal ports. A differential input transition structure includes a first layer and a second layer made of a conductive metal and a substrate positioned between the first and second layers. The second layer includes a first section that electrically connects to a single-ended signal contact point and to a first contact point of a differential signal port. The first section includes a first stub based on an input impedance of the single-ended signal contact point and a second stub based on a differential input impedance associated with the differential signal port. The second layer includes a second section that electrically connects to a second contact point of the differential signal port and to the first layer through a via housed in a pad. The second section includes a third stub associated with the differential input impedance.