Balanced Stripline Research Articles

Measurement of Magnetic Permeability Using a Differentially Excited Loop

A balanced stripline is used to provide differential excitation of a single-loop permeability measurement for increased bandwidth over dual-loop and improved sensitivity over single-loop induction methods. The proposed measurement is unique in permitting independent calibration of the permeance scale factor through a series of loop deflection tests. A simplified theoretical model of the measurement is presented together with an estimate of the expected measurement error for common-loop configurations.

Planar ultra‐wideband balun using coupled microstrip lines

A planar balun based on using parallel-coupled microstrip lines is presented. It is designed to transfer the unbalanced microstrip line to a balanced coplanar stripline as needed in many applications such as centre-fed dipole antennas. The balun includes a T-junction of stepped-impedance and tapered microstrip lines and two pairs of stepped-impedance parallel-coupled lines. The designed balun covers the band from 3 to 11 GHz with less than 0.4 dB insertion loss.

A near-field scanned microwave probe for spatially localized electrical metrology

We have developed a near-field scanned microwave probe with a sampling volume of approximately 10μm in diameter, which is the smallest one achieved in near-field microwave microscopy. This volume is defined to confine >99% of the probe’s net sampling reactive energy, thus making the response virtually independent of the sample properties outside of this region. The probe is formed by a 4GHz balanced stripline resonator tapered down to a few-micrometer tip size and provides noncontact, noninvasive measurement capability. It is uniquely suited for spatially localized electrical metrology applications, such as evaluation of Cu/low-k interconnects on semiconductor production wafers.

New coplanar waveguide/stripline feed network for seven patch hexagonal CP subarray

A novel CPW-to-stripline post coupler is demonstrated. This device couples the output power from a coax-to-CPW inphase seven-way radial power divider to a balanced stripline line stretcher and together forms a multilayer probe-type feed network. The feed network excites a seven-patch hexagonal circularly polarized (CP) subarray. The measured return loss and insertion loss of the coupler are better than 17 dB and 0.25 dB at the design frequency of 2.875 GHz. The measured on-axis axial ratio for the left hand circular polarization (LHCP) is 1.5 dB and the 3 dB beam widths are 36 deg in the principal planes of the subarray. The gain of the subarray is 13 dB. The input return loss of the subarray is better than 10 dB.

Synthesis of Balanced Stripline Branch‐Line 3‐DB Hybrid Circuit Based on Planar Circuit Model

AbstractWhen a transmission‐line type branch‐line 3‐dB hybrid is realized with a strip‐line circuit at high frequencies, electromagnetic disturbances occur near the transmission‐line junctions. Also, due to their mutual interference, the frequency characteristics are degraded from the desired ones. To treat this electromagnetic disturbance effectively, the transmission‐line type branch‐line 3‐dB hybrid circuit is separated into the branching transmission lines and the junction circuit. Based on the analysis for the function of each portion, the equivalent circuits are derived. It is described how these equivalent circuits are realized with stripline circuits with planar breadth. In practice, the balanced striplines are approximated by planar transmission line models so that the entire hybrid circuits are replaced with the planar transmission line circuits. The planar circuit theory is then applied to these structures so that the deviation from the desired hybrid characteristics due to the electromagnetic disturbance at the transmission‐line junctions is incorporated in the synthesis. Further, a hybrid circuit is designed with balanced striplines and the corresponding circuit is fabricated and tested. The measured results agree well with the theoretical frequency characteristics. Hence, the validity and effectiveness of the method are confirmed.

Analysis of balanced stripline branch‐line 3‐dB hybrid circuit based on planar circuit model

AbstractThe stripline branch‐line 3‐dB hybrid is an important circuit used frequently at microwave and millimeter‐wave frequency ranges. At high frequencies where the dimensions of the discontinuous sections with respect to the wavelength are no longer negligible, the electromagnetic disturbance needs to be included accurately in the analysis and design. In this paper, an analysis of a balanced stripline branch‐line 3‐dB hybrid is described in which such electromagnetic disturbances are taken into consideration. The balanced stripline is approximated by a planar transmission line so that the entire hybrid circuit is replaced with a planar circuit to which the planar circuit theory is applied. The paper develops a systematic analysis method. Further, based on the analysis method described here, frequency characteristics of the basic hybrid circuit are derived. The frequency range at which the characteristics start degrading, and the causes, are described.

Subpicosecond electro-optic sampling using coplanar strip transmission lines

Electrical sampling with a temporal resolution of less than 500 fs has been achieved using coplanar transmission lines on electro-optic substrates. The improved performance over the previously demonstrated balanced stripline is due to the reduced dimensions, i.e., distance between the electrodes and width of the electrodes, achievable with photolithographic technique. By further reducing the line dimensions to 10–20-μm range, this technique makes the temporal resolution of electrical waveforms in the range of 100 fs possible.

MIC Packaging Using Conductive Epoxy and Numerically Controlled Drill Techniques

A new packaging method has been developed for microwave balanced stripline circuits which combines the advantages of numerically controlled drill techniques and the low cost wellknown methods of liquid resin molding. Microwave couplers were constructed using this technique which showed excellent mechanical properties and whose electrical properties were unchanged before and after potting.

Comments on "Microstrip versus balanced stripline"

Comments on "Microstrip versus balanced stripline"

Microstrip versus balanced stripline

Mirostrip is found to exhibit lower loss than balanced strip-line of a comparable physical structure. This property is traced to conduction loss theoretically and is confirmed experimentally.

An Integrated 4-GHz Balanced Transistor Amplifier

This paper presents performance data and design information on a broadband 4-GHz balanced transistor amplifier being developed for possible use in microwave radio relay systems. The balanced stripline circuitry and passive components are integrally fabricated on a 1.5-inch-square alumina substrate using thin-film technology. A comprehensive description is presented of the circuit design, mechanical fabrication techniques, and long-term stability tests. Three-stage amplifiers give 15 dB of gain at 4 GHz with a 3-dB bandwidth of 1000 MHz. Input and output VSWR'S were below 1.05 with a noise figure of 7 dB. A mean time to failure of more than 10/sup 6/ hours has been indicated for a complete three-stage device by data obtained on accelerated component aging tests.

Resonator and Preselector in Balanced Strip Line

One of Raytheon's commercial applications involves microwave circuitry in balanced strip line, with a 3/8" spacing between ground planes. Though the less critical parts of the unit are etched in copper-clad Teflon-Fibreglas, two of the components are of higher Q than can reliably be obtained in the presence of plastic. They are: 1. a resonator, for use as a frequency stabilizing reference element in an AFC circuit; and 2. a four-stage maximally flat preselector filter. These units are made of separate strips of metal, and do not depend on the plastic sheet for their support.

Stripline Radiators

Progress on the use of strip conductors as microwave antennas indicates that the technique is flexible and economical. Broadside curtains can be fabricated with sufficient accuracy. Several types of balanced Stripline feed have been considered, and twists have been successfully built. A variety of baluns have been evaluated and used to feed colinear Franklin arrays through binary splits. Whereas in these structures the design is such as to minimize the field within the supporting dielectric, we have deliberately directed the field into the dielectric in various applications of surface waves. By etching configurations on the foil face of the dielectric, the surface index of refraction or surface reactance is controlled.