Abstract: Guanella topology balun/unun impedance transformer contains cascaded, i.e., series-coupled, coils of different sizes implemented in RF CMOS technology. The cascading of differently-sized coils provides for a large resonance-free operating bandwidth. The shunt inductive loading maximizes low frequency performance.

Abstract: A combiner coupled to output terminals of a Doherty amplifier, the combiner comprising an inverter circuit and a transformer circuit. The inverter circuit comprising at least a first network and a second network, wherein each of the first network and the second network includes lumped elements. The transformer circuit comprising at least a third network and a fourth network, wherein each of the first third and the fourth network includes the lumped elements, wherein the lumped elements are selected from the group of capacitors and inductors.

Abstract: Polar modulators include a phase splitter, a controller, variable current sources, transistor circuits, and a combiner. The phase splitter splits a RF carrier signal into quadrature component signals that are 90 degrees out of phase with each other. The controller generates modulation control signals based on information that is to be transmitted. The variable current sources each generate a variable amplitude current signal based on a different one of the modulation control signals. Each of the transistor circuits amplify a different one of the quadrature component signals with a variable amplification based on the variable amplitude current signal from a different one of the variable current sources to generate an amplitude adjusted quadrature component signal. The combiner combines the amplitude adjusted quadrature component signals from each of the transistor circuits to generate a phase-modulated RF carrier output signal.

Abstract: In a millimeter wave modulation of the direct modulation technology, the switching speed is increased and the modulation bandwidth is broadened. A millimeter wave modulator includes a millimeter wave waveguide. a switching element (PIN diode) disposed in the waveguide in which the switching element is turned on and off by a digital signal to achieve amplitude-modulation of a millimeter carrier wave propagating through the waveguide, and a shunt resistor connected to the switching element in parallel.

Abstract: A modulation apparatus connected to a termination edge of a waveguide path has a matching circuit, a detection diode for detecting a high-frequency signal inputted from the waveguide path, a resistor consumes a detection output of the detection diode, a transmission signal source controls a bias of the detection diode in accordance with a transmission signal, and a high-frequency choke. The high-frequency signal inputted when the detection diode is in a cut-off condition is reflected to the waveguide path. The high-frequency signal inputted when the detection diode is conductive is detected in the detection diode and consumed in a resistor.

Abstract: A balanced modulator has a pair of diodes, a plurality of line patterns including a balance-to-unbalance converter, the line patterns including lines extending toward and connected to the diodes, respectively, and at least a set of capacitive stubs disposed near the lines and spaced from each other by a distance of .lambda./8 (.lambda. is the wavelength at a frequency used). The capacitive stubs are connectable to the lines by bonding wires for isolation adjustments.

Abstract: A printed circuit board includes an oscillator and a modulator. The oscillator includes a first printed inductor and a capacitive diode which are printed on one side of the printed circuit board. The modulator includes a second printed inductor coupled to the first printed inductor and printed on the same side of the printed circuit board as the oscillator. A conductive surface at a reference potential is arranged the other side of the printed circuit board and in the vicinity of the oscillator and the modulator and electrically coupled to the oscillator and the modulator using conductive through holes.

Abstract: An improved modulator circuit for mixing a modulation signal with a carrier signal includes first and second harmonic mixers which are operative to produce modulated output signals at an output frequency corresponding to both the sum and the difference of the modulation signal frequency and the even harmonic frequencies of the carrier signal frequency. In one configuration employing a 90.degree. hybrid, the output signals of the harmonic mixers are combined to produce a single sideband modulated output signal. A novel harmonic mixer circuit is also provided along with demodulator circuits and methods of modulating and demodulating modulation signals.

Abstract: A push-pull modulator stage 70 has two possible transmission paths, an electrically short path (7) and a phase delay path (6) with a phase delay element providing a phase shift of approximately 180.degree.. The phase delay element has the form of a low pass filter. In each of the two paths (6, 7) a semiconductor diode (D.sub.1, D.sub.2) is disposed in such a way that they sense the carrier (U.sub.c) with a phase shift of 180.degree. and, correspondingly, switch in unison if no modulation voltage (U.sub.m) is present, thus suppressing the carrier at the signal output (3). When a modulation signal (U.sub.m) is present, the push-pull balance is disturbed and the resistance of one of the two paths (6) becomes lower relative to the other path (7), which leads to the generation of the modulated carrier voltage (Umc). The modulator stage (70) can also be designed as a dual modulator stage and/or can be used as a mixer stage.

Abstract: A microwave vector modulator (4) of the reflective type is used to match a microwave load. The adjustable reflection of the vector modulator is obtained by semiconducting surfaces (18, 19, 20, 21), illuminated by light-emitting means (24, 25, 26, 27).

Abstract: A modulator suitable for 16 quadrature amplitude modulation (QAM) is designed as a double modulator (1), wherein a 16 QAM modulator (39) consists of two double modulators (1). One double modulator (1) has two partial modulators (1',1") forming a bridge. Each partial modulator (1',1") has two possible transmission paths: (6',6") with a phase delay line (39',39") which causes a 180.degree. phase shift. On each of the two paths (6',6", 7',7"), a semiconductor diode (D.sub.1 ',D.sub.1 ",D.sub.2 ',D.sub.2 ") is disposed in such a way that they provide the carrier (U.sub.c) with a 180.degree. phase inversion and are accordingly rendered conductive in unison, if no modulation voltage (U.sub.m) is applied, whereby the carrier is suppressed at the signal output (3'). When a modulation signal (U.sub.m) is applied, the balance is changed to push-pull, and one of the two paths (6',6") assumes less impedance compared to the other path (7',7"), which leads to the generation of the modulated carrier voltage (U.sub.mc).

Abstract: A method and apparatus for modulating or demodulating a radio frequency (RF) signal which incorporates a pair of quadrature couplers. In demodulating an RF signal, an LO signal and the RF signal are each phase shifted -90 degrees by the couplers. The RF and LO signals are mixed as are the phase-shifted RF and LO signals. Each mixed signal is low-pass filtered and the filtered signals are added thereby producing an intermediate frequency signal.

Abstract: A balun section formed of a pair of transmission lines connected between separate pairs of corresponding input and output terminals with a pair of capacitors connected in series between the output terminals and another transmission line connected in series with a resistor between the circuit ground and the interconnection between the pair of capacitors. A multisection balun is constructed from a plurality of such balun sections connected in cascade. In one embodiment, the outputs of a pair of multisection baluns are supplied to a circuit such as a mixer or the like.

Abstract: In a reflective shunt-diode radio-frequency modulator the shunting diodes are spaces so that the transmission line sections between diode pairs have non-commensurate lengths. The transmission line length sections between diode pairs are selected so that a minimum in the frequency/attenuation curve resulting from one transmission line section/diode pair is cancelled by a maximum in the frequency/attenuation curve from another transmission line section/diode pair. The superposition of the frequency characteristics from all transmission line section/diode pairs results in a structure in which reactive cancellation occurs over the entire operating frequency range. Consequently, it is not necessary to saturate the shunting diodes at the low band end to maintain maximum attenuation. In addition, to improve insertion loss, capacitive stubs are located along the transmission line which modify the filter characteristics when the shunting diodes are turned "off".

Abstract: An amplitude modulator for mixing multifrequency signals characterized in that there are combined a mixer for producing a mixed signal by mixing not less than two alternating current signals with different frequency and a signal generator for the modulator to modulate the mixed signal by applying modulation signal to the mixed signal. According to the present invention, the device can be simplified and miniaturized in comparison with the conventional one since the mixer and amplitude modulator are incorporated in the present invention, whereby reliability of the device is greatly improved.