Unilateral microstrip balanced and doubly balanced mixers

Abstract

Possibilities for the uniplanar realisation of balanced and doubly-balanced microstrip mixers a r e discussed. Several novel mixer designs a r e presented, which can be used for miniaturization or for broadbanding t h e performance, using simple and noncritical branchline structures. The feasibility of the structures is verified experimentally. Relative bandwidths u p to approximately 45% a r e reached uniplanar circuits a r e much easier to fabricate, a r e more reliable, and a r e amenable for monolithic integration or realization on dielectric substrates with thick metal backings. With respect to such techniques, metallized via holes and air bridges can be tolerated ( a s it is needed for example for a Lange-

A C‐band injection‐locked balanced oscillator for direct‐conversion QPSK modulation applications

“…Injection-locked oscillators with balanced topologies were first reported in [6] for use in phased-array synchronized oscillators. The balanced oscillator presented in the literature [7] is capable of providing anti-phase outputs itself, without the use of complex external resonators, 180°phase shifters, or baluns, however, the extended resonance technique was used [8].…”

“…Several microstrip antennas designed for circular polarization with single feed can be found in the literature [4 -5]. Linearly polarized microstrip elements are used in a four-element planar array with sequential rotation feeding to produce circular polarization [6]. Single-fed circularly polarized elements are also used in sequential rotating pairs of elements to improve the cp axial ratio and improve the bandwidth [4,7].…”