Misao Haneishi

76GHz alternating-phase fed single-layer slotted waveguide arrays with suppressed sidelobes in the E-plane

Sidelobe suppression of the alternating-phase fed array in the E-plane is discussed. The T-junctions for the alternating-phase fed waveguide array are designed for Taylor pattern with sidelobe level of -25dB. The validity of the design of the power divider consisting of T-junctions for sidelobe suppression is confirmed.

Radiation properties of microstrip array antenna fed by radial line

The authors present an array antenna which excites a singly fed circularly polarized microstrip antenna via a low-loss radial waveguide. In order to check the performance of this antenna, some planar arrays were fabricated and tested at the SHF band. Satisfactory performance was obtained in both radiation pattern and directivity gain. This type of array demonstrated high-efficiency performance (approximately 90% aperture efficiency). It was confirmed that this type of antenna can be a useful model of a circularly polarized planar antenna.<<ETX>>

An Alternating-Phase Fed Single-Layer Slotted Waveguide Array in 76 GHz Band and Its Sidelobe Suppression

This paper presents designs and performances of 76 GHz band alternating-phase fed single-layer slotted waveguide arrays. Two kinds of design, that is, uniform aperture illumination for maximum gain and Taylor distribution for sidelobe suppression of −25 dB, are conducted. High gain and high efficiency performance of 34.8 dBi with 57% is achieved for the former, while satisfactory sidelobe suppression of −20 dB in the H-plane and −23 dB in the E-plane with high efficiency is confirmed for the latter. The simple structure dispensing with electrical contact between the slotted plate and the groove feed structure is the key advantage of alternating-phase fed arrays and the slotted plate is just tacked on the feed structure with screws at the periphery. High gain and high efficiency performances predicted theoretically as well as design flexibility of the alternating-phase fed array are demonstrated in the millimeter wave frequency. key words: alternating-phase, slotted waveguide array, planar antenna, millimeter wave, sidelobe suppression

Alternating-phase fed single-layer slotted waveguide arrays with wide chokes at 76 GHz band

In this paper, the alternating-phase fed array with chokes is applied to the 76 GHz band. Two types of contact, just screwed at the periphery and tightly contacted by thermo compression bonding, are tested and compared.

Circularly polarized planar antenna excited by cross-slot coupled coplanar waveguide feedline

A circularly polarized planar antenna using a coplanar waveguide (CPW) feeding system which is coupled using a symmetrical crossed slot is proposed and is experimentally investigated. The experimental results confirmed high performance for the radiation pattern as well as the impedance characteristic of the circular patch antenna. Moreover, the circularly polarized subarray unit (CP-SAU) has also been fabricated and tested at the C band.

Radiation properties of ring microstrip antenna fed by symmetrical cross slot

The microstrip ring antenna (R-MSA) system has been studied by many researchers, because it is possible to reduce the antenna size. However, since the R-MSA has high impedance characteristics at the feeding point, impedance matching is difficult. We investigate the R-MSA element fed by a symmetrical crossed slot (SCS-R-MSA) which easily permits impedance matching. We describe a new type of dual polarized planar antenna with two-port lines coupled to the R-MSA through a symmetrical crossed slot. A circularly polarized planar antenna using this R-MSA as a radiating element and its array are described. In order to evaluate the performance, some planar antennas were tested at C-band. In this experiment, the basic design of both the dual and circularly polarized planar antenna systems were investigated.

Circularly polarized microstrip antennas for frequency control with a variable reactance

This paper presents circularly polarized microstrip antennas (CP MSA) for frequency control with a variable reactance. Operating frequency of circular polarization of the proposed antennas can be controlled by the variable reactance. 8% bandwidth with axial ratio less than 3 dB and over 3 dBi gain is obtained by the proposed CP MSA. In order to enhance the CP bandwidth, a stacked CP MSA for frequency control with the variable reactance is also designed. 23% bandwidth with axial ratio less than 3 dB and over 7 dBi gain is achieved by the stacked CP MSA. Stable LHCP radiation patterns with low cross polarization are observed in the CP bandwidth for the both CP MSAs. The variable reactance is realized by one varactor diode, therefore, it is demonstrated that frequency control of the proposed CP MSAs is accomplished by one varactor diode.

Radiation Properties of Multiband Circular MSA with Half-Ring Slots

SUMMARY Novel multiband circular microstrip antennas (C-MSAs) with multiple half-ring slots are presented in this paper. Two antennafeeding systems, i.e. an embedded L-probe beneath the patch and a coplanar circular arc- shaped probe (T-probe), are used to feed the C-MSA with multiple half-ring slots. The embedded L-probe is used to excite the CMSA with a double-layer dielectric substrate due to its tremendous performance to provide a wideband impedance matching. The coplanar T-probe is proposed to realize an excellent multiband C-MSA in a single-layer structure. The C-MSA with four half-ring slots fed by the embedded Lprobe exhibits satisfactory radiation characteristics. Five frequencies with broadside radiation patterns and gains of at least 5.0 dBi are obtained. It is also confirmed by simulation that resonant frequency and gain can be easily controlled to meet the desired frequency requirements. Moreover, the C-MSA with three half-ring slots fed by the coplanar T-probe presents satisfactory performance over the four observed frequencies with good return losses (−10 dB reference). Broadside radiation patterns with acceptable cross-polarization level and gains in the range of 3.0–7.0 dBi are obtained. Couplings between the C-MSA and the coplanar T-probe have an important contribution to obtain good return losses. It can be controlled by adjusting the distance between them and the arc angle of the coplanar T-probe appropriately. Experiments of both types of antenna were conducted to verify the simulation results and good agreements are confirmed. Due to the performances, these two C-MSAs are considered to be an effective model as a

Ku-band planar array using ring shaped patch antenna

The basic configuration of a triplate-type planar antenna composed of a ring-shaped patch (R-TPA) is described. The configuration of a circularly polarized R-TPA array designed for the frequency band of 11.7 GHz to 12.0 GHz is also described. The authors also present the radiation properties: radiation pattern, frequency characteristics of return loss, axial ratio, gain, and aperture efficiency.<<ETX>>

Inverted triangle printed monopole antenna with halfdisk for UWB applications

A novel printed monopole antenna for UWB applications is presented in this paper. A monopole with a combination of a half-disk and an inverted triangle is installed on a finite ground plane. A slit on the ground plane performs as an impedance controller to obtain matching over wide frequency range. Impedance bandwidth of more than 1:6 is achieved with VSWR<2. Omni-directional patterns are confirmed by simulation and experiments as well. Excellent gain performance is also achieved by the proposed antenna.