A novel broad-band ring-slot array antenna for simultaneous use of orthogonal polarizations is presented in this paper. In this antenna, the broad-band performance is obtained by integrating a 22 ring-slot array antenna and a broad-band π/2 hybrid circuit. The simultaneous use of the right-hand circular polarization (RHCP) and the left-hand circular polarization (LHCP) is achieved using orthogonal feed circuits on three layers. The both-sided MIC technology is effectively employed in forming this type of slot array antenna. Experimental results show that the proposed antenna has good circular polarization characteristics for both the LHCP and the RHCP. The measured impedance-bandwidth of return loss better than -10 dB are about 47% both for the LHCP and the RHCP. The 3 dB axial ratio bandwidths are 25% (RHCP) and 29% (LHCP). The isolation between the two input ports is better than -35 dB at center frequency of 7.5 GHz.

In this paper, a novel circuit structure of Push-Push oscillator using λg/2 microstrip resonator is proposed, in which a common resonator plays two functions of frequency determining and power combining. This type of Push-Push oscillator is named "Dipole Resonator Push-Push oscillator" here, where an additional power combiner circuit required in conventional Push-Push oscillators can be eliminated. The Push-Push oscillator adopting this design concept has the advantages of the easy circuit design, the simple circuit structure and the miniaturization of the circuit size. As a most simple example of this design concept, a K-band Push-Push oscillator using a λg/2 microstrip resonator is designed and achieved. The high output power of +8.4 dBm at the frequency of 21.68 GHz (2f0) is obtained with the phase noise of -100.5 dBc/Hz at the offset frequency of 1 MHz. Besides, a high suppression of the undesired fundamental frequency signal (f0) of -26 dBc is realized.

In this paper, a 20 GHz push-push oscillator using a ring resonator is proposed. The push-push oscillator adopts "dipole resonator push-push oscillator" circuit scheme, in which a common resonator plays two roles of frequency determining and power combining, and then the additional power combiner circuit required in conventional push-push oscillators can be eliminated. This kind of push-push oscillators has the advantages of the easy circuit design, the simple circuit configuation and the miniaturization of the circuit size. The output power is +4.5 dBm at the frequency of 20.34 GHz (2f0) with the phase noise of -98 dBc/Hz at the offset frequency of 1 MHz, and a high suppression of the undesired the fundamental frequency signal (f0) of -33 dBc is obtained.

A novel millimeter wave quadruple-push oscillator is presented in this paper. The quadruple-push oscillator consists of four identical sub-circuits and a ring resonator that is used as a common resonator. It is well known that there are two orthogonal resonant modes on a one-wavelength ring resonator. According to this resonant characteristic, two orthogonal push-push oscillations can be set up in the quadruple-push oscillator, and there is a phase difference of 90among four sub-circuits due to nonlinear performance. Therefore, the four identical sub-circuits can oscillate at the same fundamental frequency f0, and the fundamental oscillating signal of one sub-circuit has phase differences of 90, 180and 270to that of the others, and the desired fourth harmonic signals can be combined due to their in phase relations, and the undesired fundamental signals, the second harmonic signals, the third harmonic signals and so on can be suppressed when the oscillating signals of the four sub-circuits are added in phase. The principle is firstly explained in this paper, and is proved in the experiment of a Ka-band quadruple-push oscillator. The measured output power of the desired fourth harmonic signal (4f0) was +1.67 dBm at the frequency of 35.8 GHz. The measured suppression of the undesired signals of the fundamental signal (f0), the second harmonic signal (2f0), the third harmonic signal (3f0) and the fifth harmonic signal (5f0) were -18.0 dBc, -17.9 dBc, -17.8 dBc and -35.5 dBc, respectively. The measured phase noise performances at 35.8 GHz were -104.0 dBc/Hz and -82.3 dBc/Hz at the offset frequency of 1 MHz and 100 kHz, respectively.

This paper describes very compact MIC magic-Ts and their integration with planar array antennas to realize the advanced antenna modules. The orthogonal transmission modes are effectively used to arrange the preferable port layout of magic-Ts. This flexible port layout of magic-Ts is a practical feature for integration with planar array antennas. The integration of magic-Ts and planar array antennas can easily create advanced functions. A couple of array antennas based on the integration advantages are introduced to materialize this technical concept. This integration approach is of big worth to originate various kinds of advanced antennas and the wireless modules in the ubiquitous society.

This paper presents an advanced and extensive utilization approach of microwave resonant fields, and the applications to push-push oscillators and reconfigurable planar antennas. The excellent coherency, synchronous harmonics and the degenerative orthogonal modes of electromagnetic field built up on microwave resonators are noticeable features in this approach. Another crucial point is the resonant field controllability that is especially essential feature for reconfigurable antennas in this paper. All the features can be realized by embedding semiconductor devices and/or IC's on a microwave resonator. Push-push oscillators and reconfigurable planar antennas are described as good examples of this approach. The push-push oscillators can generate very higher frequency signals due to the selective use of the 4th harmonic up to the 8th harmonic resonant fields, suppressing undesired harmonic signals. As a result, very high frequency band oscillators up to millimeter-wave bands with good suppression of undesired harmonic signals can be easily realized at very low cost by use of commercially available active devices for low frequency bands. The reconfigurable planar antennas are also demonstrated, where the boundary condition of the resonant field on planar antennas can be purposefully controlled to realize reconfigurable antenna performances by the semiconductor devices embedded on the patch as well. The orthogonal linear polarization controllable patch, the dual-band switching patch and the continuously frequency controllable patch have been demonstrated as the successful applications of this approach.

Novel, very small-size multilayer MMIC's using miniature microstrip lines on a thin dielectric film, as well as the features of the multilayer structure, are presented. Very narrow-width thin-film transmission lines, meander-like configurations, line crossovers, and vertical connections, which are effective for significant chip-size reduction and flexible layout, are realized and utilized in a 2.5-3 µmN-layer dielectric film structure. 180-degree and 90-degree hybrids and umltiport Wilkinson dividers, which are implemented in small areas of 0.1 mm2 and 1.7 mm2, are presented. Furthermore, layout flexibility in the multilayer structure is demonstrated by implementing distributed amplifiers into the layers.

A novel push-push oscillator taking advantages of "Double-Sided MIC Technology" is proposed. The oscillator incorporates microstrip lines on a dielectric substrate and a slot line on the reverse side. By integrating a slot line and microstrip lines, the push-push oscillator can be realized very easily. All the concerned undesired harmonic signals (f0, 3f0 and 4f0) can be suppressed satisfactorily. Using these approaches, a push-push oscillator in K-band is designed and fabricated. The output power of +4.17 dBm at the frequency of 21.25 GHz is measured. All the undesired signals are sufficiently suppressed to be better than -30 dBc. The phase noise is -99.68 dBc/Hz at the offset frequency of 1 MHz.

This paper represents a low noise second harmonic oscillator using mutually synchronized Gunn diodes. A multi-layer MIC technology is adopted to reduce the circuit size of the oscillator. The oscillator consists of Gunn diodes, slot line resonators and strip lines. By embedding Gunn diodes in the slot line resonators, a harmonic RF signal can be generated very easily. The strip lines are used for the power combining output circuit. The shape of slot line resonator is square in order to achieve the low phase noise and the suppression of undesired harmonics. The second harmonic oscillator is designed and fabricated in K band. The output power is +8.89 dBm at the design frequency of 18.75 GHz (2f0) with the phase noise of -116.2 dBc/Hz at the offset frequency of 1 MHz. Excellent suppression of the undesired fundamental frequency signal (f0) of -33 dBc is achieved. Also, the circuit size is reduced by three-tenths relative to that of the previously proposed circuit.

This paper represents a novel second harmonic power combining oscillator using mutually synchronized Gunn diodes embedded on slot line resonators. A both-sided MIC technology is adopted in the oscillator. The oscillator consists of Gunn diodes, slot line resonators and microstrip lines. By embedding Gunn diodes on the slot line resonators, the harmonic RF signal can be generated very easily. The microstrip lines are used for the power combining output circuit. This oscillator has advantages such as easy circuit design, simple circuit configuration and miniaturization of the circuit size. The second harmonic oscillator is designed and fabricated in K-Band. The output power is +5.75 dBm at the design frequency of 19.0 GHz (2f0) with the phase noise of -111.7 dBc/Hz at the offset frequency of 1 MHz. Excellent suppression of the undesired fundamental frequency signal (f0) of -39 dBc is achieved.

An injection locked coupled push-push 3-oscillators array using unilateral coupling circuits is proposed. The circuit consists of unit oscillators and coupling circuits. For the unit oscillator, a dual-band push-push oscillator which generates the fundamental signal (f0) and the second harmonic signal (2f0) is adopted. The output signal of the oscillator array is the second harmonic signal. The fundamental signal is used for the injection signal to synchronize oscillators. These adjoining unit oscillators are connected by the coupling circuits. The coupling circuit is composed of a buffer amplifier and a phase shifter. Due to the advantage of the push-push oscillator, the phase shift between the adjoining oscillators is twice as large as that of the phase shift in the coupling circuit. The oscillator array is designed in Ku-band. Three push-push oscillators are arrayed and include two coupling circuits which are designed and fabricated. The phase shift of 190.0 degrees between the adjoining unit oscillators is demonstrated.

In this paper, the 8th harmonic Push-Push oscillator is successfully presented. The Push-Push principle and the excellent harmonic coherency in a microwave resonator are effectively utilized. The proposed oscillator consists of two sub-circuits, a microstrip ring resonator and an output circuit. The concept of the simplified structure harmonic oscillator (SSHO) is adopted in the proposed oscillator. The microstrip ring resonator plays two roles of the common resonator and the power combiner circuit. This kind of Push-Push oscillator has practical advantages of the easy circuit design due to the simple circuit configuration and the miniaturization of the circuit size. Using the Push-Push principle and the effective circuit configuration of the output circuit, the desired 8th harmonic signal is effectively enhanced. This Push-Push oscillator achieves good millimeter-wave oscillation in V band using inexpensively available X band HEMTs. The estimated output power of -6 dBm at the frequency of 51 GHz is obtained with the phase noise of -93 dBc/Hz at the offset frequency of 1 MHz.