Balun

About: Balun is a research topic. Over the lifetime, 5375 publications have been published within this topic receiving 52256 citations. The topic is also known as: Telephone balance unit.

High frequency composite part

Abstract: PROBLEM TO BE SOLVED: To provide a high frequency composite part which has a laminated structure with a balun transformer and two matching circuits, and in which the two matching circuit parts can hold the same characteristics. SOLUTION: An insulating substrate 7 has function layers 71 to 83. A balun transformer part 31 includes a first to fourth line conductors 311 to 314 and is disposed between the function layers 72 to 74. A first matching circuit 32 is connected to one end of a third line conductor 313, and a second matching circuit 33 is connected to one end of a fourth line conductor 314. The first and the second matching circuits 32 and 33 are mounted between the same function layers 75 and 76. COPYRIGHT: (C)2005,JPO&NCIPI

Compact Endfire Coupled-Mode Patch Antenna With Vertical Polarization

Abstract: Coupled-mode patch antenna (CMPA) is able to reform the beam by manipulating the phase of the fringing fields at the edges. In this paper, a method is proposed to realize endfire radiation with vertical polarization based on the concept of CMPA. Besides the phase controlled by the coupling, the asymmetric feeding introduces additional phase shift to one of the radiation slots, which makes the beam pointing to the forward endfire direction within the whole band. The ground of the antenna is truncated to be the same size of the top patch, which eliminates the undesired effect of the ground edge and ensures the symmetric patterns pointing around endfire direction. The size of the antenna itself is only $0.26\lambda _{0} \times 0.44\lambda _{0}$ , where $\lambda _{0}$ is the free-space wavelength at the center operating frequency. In order to block the unwanted common mode current outside the feeding coaxial cable, a quarter-wavelength balun is applied in the implementation. The fabricated antenna sample has highly selective two-pole $S_{11}$ response with center frequency of 2.41 GHz and 10 dB fractional bandwidth of 2.5%. The simulated and measured patterns confirm the endfire radiation of the proposed antenna. The measured 3 dB bandwidth of realized gain at forward endfire is 2.5% at center frequency of 2.41 GHz, where the realized gain is 2.8 dBi and the front-to-back (F/B) ratio is 17.1 dB. The proposed endfire antenna with vertical polarization has the advantages of its inexpensive and friendly fabrication, compact and simple configuration, and high selectivity.

Extremely Broadband Slot Spiral Antenna with Shallow Reflecting Cavities

Abstract: Previously, the broadband spiral class of antennas primarily consisted of the wire (or "printed")spiral and spirals with approximately complementary geometry. While both are very broadband radiators, they are still somewhat band-limited due to their associated balun structures, and bulky as a result of their absorbing cavities. A new type of spiral antenna utilizing slot radiating elements is presented that eliminates these drawbacks, relying instead on several new approaches to guarantee its frequency-independent operation over extremely broad bandwidths. The design and integration of a planar infinite balun/feed structure and very shallow reflecting cavity is presented and discussed, as is a new termination technique. Gain, axial ratio, and pattern measurements for both a 6" (15.24 cm)diameter spiral, with flow = 750 M Hz and 6.25:1 bandwidth, and an 18" (45.72lcm) diameter spiral, with flow = 250 M Hz and 15:1 bandwidth, are also given and reviewed.

A novel design for UHF near-field RFID reader antenna based on traveling wave

Abstract: A novel planar antenna is presented for ultra high frequency (UHF) near-field radio frequency identification (RFID) applications. The antenna is composed of grounded coplanar waveguide, coplanar stripline, a lumped balun, multiple resistances and a finite-size ground plane. The load impedance is equal to the characteristic impedance of the coplanar stripline, so traveling wave can transmit along the coplanar stripline. The proposed structure can make large currents along the coplanar stripline so that a strong and uniform magnetic field distribution is excited in the region around the antenna. The antenna geometry, design concept, simulated and measured results are carefully discussed throughout the paper. Measurements show that the antenna operating with a commercial reader demonstrates good performance of tag identification with inductive coupling for near-field RFID applications.

BALUN circuit for combining differential power amplifier outputs

Abstract: A BALUN circuit comprising a lead network coupled to the positive phase output of a differential power amplifier, a negative phase output coupled to the negative phase output of the differential amplifier, and a delay element coupled in series with the lag network. The output of the lead network and the delay element are combined to form a single-ended output. The lag and lead networks may adjust the output impedances of the positive and negative phase outputs so that the output impedance of the single-ended output is set to a desired value. In one implementation, selected components of the lag and lead networks, and the delay element, comprise printed elements.