Showing papers on "Balun published in 2016"

Metamaterial substrate for circuit design

Abstract: This invention enables Frequency Selective Surface (“FSS”) and Artificial Magnetic Conductor (“AMC”) which exhibits Electromagnetic Band Gap (“EBG”) in any of the substrate's layer from a small and thin systems and sub-systems in package to a large-format PCBs. The metamaterial substrate may be integrated with electronic circuit components or buried in PCBs for circuit designs capable of transmitting, receiving and reflecting electromagnetic energy, altering electromagnetic properties of natural circuit materials, enhancing electrical characteristics of electrical components (such as filters, antennas, baluns, power dividers, transmission lines, amplifiers, power regulators, and printed circuits elements) in systems and sub-systems circuit designs. The metamaterial substrate creates new electrical characteristics, properties and systems, sub-systems or component's specification not readily available with conventional circuit materials, substrates, and PCBs. The metamaterial substrate can be less than 70 μm thick and buried into any PCB layer.

Ultrawideband Array With 70° Scanning Using FSS Superstrate

Abstract: We present a wideband tightly coupled dipole array (TCDA) with integrated balun and a novel superstrate consisting of printed frequency selective surface (FSS) for wide angle scanning. Although previous TCDAs have had decent scanning performance up to ±60°, use of dielectric superstrates are usually required, resulting in additional cost and fabrication complexity. In this paper, we replace the bulky dielectric layer(s) with periodic printed elements and yet achieve wide-angle and wideband impedance matching. The proposed approach provides superior performance of 6.1:1 bandwidth (0.5–3.1 GHz) with VSWR $E$ plane, ±70° in $D$ plane and ±60° in $H$ plane. The FSS, radiating dipoles and feed lines are designed and fabricated on the same vertically oriented printed circuit board, resulting in a low-cost and lightweight structure as compared to other low profile arrays. Measured scanning patterns of a $12 \times 12$ prototype are presented, showing good agreement with simulations.

A 340-GHz Heterodyne Receiver Front End in 40-nm CMOS for THz Biomedical Imaging Applications

Abstract: A low-power and high-performance 340-GHz heterodyne receiver front end (RFE) optimized for terahertz (THz) biomedical imaging applications is proposed in this paper. The THz RFE consists of an on-chip patch antenna, a single-balanced mixer, and a triple-push harmonic oscillator. The oscillator adopts a proposed harmonic oscillator architecture which can provide differential output by extracting output signals from the same current loop without any additional balun required. The mixer biased in the subthreshold region is designed not only to have high conversion gain and low noise figure by choosing the output intermediate frequency well above the flicker-noise corner frequency, but the required local oscillator (LO) power can also be as low as –11 dBm. Such a low demand on the LO power makes the proposed mixer very suitable for THz applications in which the achievable LO power is very limited. The impact of unavoidable slots for passing design rule checks on the performance of an on-chip patch antenna is also presented. The proposed THz RFE is implemented in a 40-nm digital complementary metal–oxide–semiconductor technology. The measured voltage conversion gain is –1.7 dB at 335.8 GHz, while the mixer and the oscillator only consume 0.3 and 52.8 mW, respectively, from a 1.1 V supply. The proposed THz RFE is employed to set up a THz transmissive imaging system which can provide spatial resolution of 1.4 mm.

A $K$ -Band Frequency Doubler With 35-dB Fundamental Rejection Based on Novel Transformer Balun in 0.13- $\mu \text{m}$ SiGe Technology

Abstract: A compact balanced frequency doubler with more than 35 dB odd-harmonic rejection and fractional bandwidth of 73% is presented in this letter. Wide bandwidth and high odd-harmonic suppression is achieved by adopting a new technique for the transformer balun design, resulting in a very low magnitude imbalance of 0.13 dB and a phase imbalance of 0.4° over 7–15 GHz. The balun performance is improved by offsetting the radius of the primary and secondary coils, which reduces the parasitic coupling capacitance. The input and output frequency ranges for the doubler are 7–15 GHz and 14–30 GHz respectively. The circuit was fabricated in 0.13- $\mu \text{m}$ SiGe technology. The chip size is 0.6 mm $\times \, 0.4$ mm.

Low-Loss Integrated Passive CMOS Electrical Balance Duplexers With Single-Ended LNA

Abstract: A tunable integrated electrical balanced duplexer (EBD) is presented as a compact alternative to multiple bulky surface acoustic wave (SAW) and bulk acoustic wave (BAW) duplexers in third-generation (3G)/fourth-generation (4G) cellular transceivers. A balancing network creates a replica of the transmitter (TX) signal for cancellation at the input of a single-ended low-noise amplifier (LNA) to isolate the receive path from the TX. The proposed passive EBD is based on a cross-connected transformer topology without the need of any extra baluns at the antenna side. The balancing network enables a single-ended LNA with reliable high TX power operation up to 22 dBm by alleviating the common-mode coupling. The duplexer achieves around 50-dB transmitter–receiver (TX-RX) isolation within a 1.6–2.2-GHz range. The cascaded noise figure (NF) of the duplexer and LNA is 6.5 dB, and TX insertion loss (TXIL) of the duplexer is about 3.2 dB. The duplexer and LNA are implemented in a ${\hbox{0.18-}}\mu{\hbox{m}}$ CMOS process and occupy an active area of ${\hbox{0.35 mm}}^{2}$ .

Integration Design of Filtering Antenna With Load-Insensitive Multilayer Balun Filter

Abstract: Integration design of a filtering antenna fed by a load-insensitive multimode balun bandpass filter is proposed in this paper. The balun filter is designed and realized using multilayer structure for miniaturization. To be directly integrated into the antenna, both amplitude and phase performances of the balun filter are investigated with different complex load impedances. With insensitive responses against the load, this balun filter is utilized to design a filtering antenna as the feeding of a quasi-Yagi antenna, which is considered as a frequency-dependent differential complex load. The radiation characteristics are improved by applying a metallic shield as the package for the proposed design. To verify the design concept, an experimental filtering antenna is designed, fabricated, and measured with almost the same passband as that of the balun filter benefiting from the load-insensitive property of the latter. The simulated and measured results are presented, showing good agreement.

A High Efficiency E-Band CMOS Frequency Doubler With a Compensated Transformer-Based Balun for Matching Enhancement

Abstract: This letter presents a broadband high efficiency frequency doubler based on a new and effective compensation technique. A transformer based input balun achieves good balanced performance and input matching by the newly invented central capacitor based compensation technique. It demonstrates a peak conversion gain (CG) of $-$ 2.5 dB and peak efficiency of 9.7% with a saturated output power of 2.5 dBm at 74 GHz. The doubler exhibits a 3 dB CG bandwidth of 28 GHz from 62 to 90 GHz. The fundamental rejection is larger than 20 dB. The doubler is fabricated in a 65 nm CMOS technology with chip area of $0.6\times 0.45\ {\rm mm}^{2}$ and consumes 9–14 mW power.

A New Approach to Design Microstrip Wideband Balun Bandpass Filter

Abstract: A new design method of microstrip wideband balun bandpass filter (BPF) is presented in this letter. By utilizing the standing-wave property of voltage distribution along an open-circuited half-wavelength $(\lambda/2)$ microstrip transmission line, the out-of-phase signals can be obtained at two output ports of a balun. Meanwhile, proper coupling topologies between the open-circuited $\lambda/2$ microstrip transmission line and the multi-mode resonators are selected to achieve a balun BPF with both characteristics of balance performance and wideband filtering properties. To validate our proposal, a balun BPF operating at 1 GHz with a 3 dB FBW of 30% is designed, fabricated, and measured. Both the simulation and measurement results of the designed balun BPF are provided with a good agreement. Results indicate that this balun BPF exhibits not only a high selectivity filtering performance with two common transmission zeros (Tzs) of ${\mathrm S}_{21}$ and ${\mathrm S}_{31}$ outside the passbands, but also a good balance performance with 0.5 dB amplitude imbalance and 5 $^{\circ}$ phase imbalance.

Study of a New Planar-Type Balun Topology for Application in the Design of Balun Bandpass Filters

Abstract: A comprehensive study of a new planar-type balun prototype is presented in this paper for application in the design of balun bandpass filters (BPFs) with widely used open-type resonators. The proposed balun is in general composed of two identical back-to-back quarter-wavelength ( $\lambda $ /4) coupled line sections. The design concept originates from the analysis of the standing wave pattern on a half-wavelength ( $\lambda $ /2) open-circuited transmission line. After an intuitive illustration is given, its working principle is presented to validate the feasibility of the proposed balun. Afterward, two types of the coupled line prototypes are analyzed to implement the proposed balun with filtering response, whereas a basic rule is given to realize the transmission zeros. To further demonstrate the validity of the proposed balun prototype, two practical balun BPFs with common dual-mode resonators are designed and fabricated. As expected, transmission zeros are generated near the desired passband of our presented balun filters, thereby improving their frequency selectivity. Both simulated and measured results exhibit good filtering and balun performance.

A New Approach to Design a Microstrip Dual-Mode Balun Bandpass Filter

Abstract: A new approach to design a microstrip dual-mode balun bandpass filter (BPF) is proposed in this letter. Its working principle is extensively explained by analysis of standing wave pattern on a half-wavelength $(\lambda/2)$ open-circuited transmission line. By selecting proper coupling topologies between the $\lambda/2$ open-circuited transmission line and dual-mode open-stub loaded resonators, a novel planar type dual-mode balun BPF is presented in this letter. To validate the feasibility of the new approach, a dual-mode balun BPF operating at 2.0 GHz with 0.35 dB magnitude imbalance and 5 $^{\circ}$ phase imbalance is designed and fabricated. Both simulated and experimental results are provided with good agreement.

Compact LTCC Balun With Bandpass Response Based on Marchand Balun

Abstract: In this letter, we present a compact low temperature co-fired ceramic (LTCC) balun with bandpass responses. It is designed based on a Marchand balun. The half- and quarter-wavelength transmission lines in Marchand balun are utilized as resonators in this design. Three feeding lines, functioning as input and outputs, are coupled to the resonators. The 180° phase difference between two output ports is achieved due to the inherent out-of-phase characteristic at the two open ends of the half-wavelength resonator. The bandpass responses are enabled by only adding three coupling lines and thus compact size is obtained. The coupling matrix is utilized in the design for realizing the good filtering responses and the design guideline is presented. For demonstration, a LTCC balun filter centered at 5.5 GHz is implemented. Good agreement between the simulated and measured results validates the proposed idea. The core circuit size is only $2\ \text{mm}\times 1.7\ \text{mm}\times 1.6\ \text{mm}$ or $0.089\lambda_{g}\times 0.076\lambda_{g}\times 0.071\lambda_{g}$ .

Wideband balun bandpass filter explored for a balanced dipole antenna with high selectivity

Abstract: A novel microstrip wideband balun bandpass filter (BPF) is presented for development of a balanced dipole antenna with wide operating band and high frequency selectivity. By utilising the standing-wave property of current distribution along a half-wavelength (λ/2) open-ended microstrip line, out-of-phase signals are ideally obtained at two output ports of a balun. Meanwhile, proper coupling topologies between the open-circuited λ/2 microstrip transmission line and the quadruple-mode resonators are selected to achieve a balun BPF with both characteristics of balanced performance and wideband filtering properties. A balun BPF operating at 1.65 GHz with 32% fractional bandwidth is at first designed. The derived results not only exhibit good performance with 0.49 dB amplitude imbalance and 7.2° phase imbalance, but also achieve high selectivity relying on two transmission zeros. Next, this balun BPF is integrated with a balanced dipole antenna with a flat shape towards wideband and high-selective radiation. Both simulated and measured results achieve higher than 10 dB return loss and 2.4 dBi radiation gain over a band of 1.4–1.9 GHz.

Coupled-Line Sensor With Marchand Balun as RF System for Dielectric Sample Detection

Abstract: A novel nondestructive method for effective permittivity measurement and detection of sample’s permittivity change in microwave frequency range has been proposed, utilizing a Marchand balun and a coupled-line sensor. The out-of-phase excited coupled-line section is used to obtain high sensitivity on the covering sample, which can be as narrow as the spacing between coupled strips. Formulas describing balanced to unbalanced impedance transformation of a Marchand balun have been provided, hence the proposed method requires only one-port measurement to determine effective permittivity in a wide frequency range. The proposed setup has been theoretically and experimentally investigated. The obtained measurement results proved the usefulness of the proposed approach for dielectric sample detection.

Multi-layer archimedean spiral antenna fabricated using polymer extrusion 3D printing

Abstract: This work describes the design, fabrication, and testing of an Archimedean spiral or spiral antenna using polymer extrusion 3D printing of polycarbonate base material. The spiral antenna design was simulated using CST Microwave Studio (R), and the resulting 3D printed antenna characterized in terms of return loss, directivity, and polarization. The antenna design was embedded into a 3D printed structure using a unique ultrasonic method while a ground plane was inserted through a thermal embedding process. These fabrication methods provide process flexibility, which allows multiple conductive antenna layers to be additively constructed in a single build sequence. The method described can be used to create unique electromagnetic structures such as waveguides directly in a 3D printed dielectric part. The spiral antenna was tested with three variations of microstrip feed line used to match 50 impedance and introduce a 180 degrees phase shift between the two arms of the spiral. These include a Duroid balun attached to feed of the antenna after fabrication, a Duroid balun embedded into the polycarbonate during fabrication, and the same microstrip design fabricated out of copper mesh and embedded into the structure using the polycarbonate as a dielectric substrate. The results of these three approaches will be discussed. (c) 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1662-1666, 2016

Compact microstrip balun diplexer using stub-loaded dual-mode resonators

Abstract: A new microstrip unbalanced-to-balanced (balun) diplexer based on stub-loaded dual-mode resonators is presented. The proposed balun diplexer primarily consists of two balun filter channels, and both channels are entirely independently designable, thus bringing great flexibility in the balun diplexer design. Besides, owing to the direct connection of two dual-mode balun filters, no additional matching networks are demanded at the common input port, leading to a significant size reduction. For demonstration, a prototype balun diplexer operating at 2.30 and 2.72 GHz is implemented. Both simulated and experimental results are provided in good agreement.

Compact quasi‐Yagi antenna with folded dipole fed by tapered integrated balun

Abstract: Planar quasi-Yagi antennas including a printed balun are designed and experimentally characterised. The parasitic array driver is a folded dipole connected to a parallel stripline. The unbalanced to balanced transition between the input microstrip and the folded dipole terminals is obtained by linearly tapering both the microstrip and the ground plane widths. These printed antennas are more compact and directive than their counterparts based on resonant half-wavelength dipole drivers: indeed, in the presence of one director, the size of the board is about 0.4 λ0 × 0.5 λ0 and the measured gain is 7 dB.

A Planar Dual-Band Coupled-Line Balun With Impedance Transformation and High Isolation

Abstract: This paper proposes a novel planar dual-band coupled-line balun with impedance transformation and high isolation. Closed-form design equations are obtained based on the classical even-odd mode equivalent approach. For convenience of designing and synthesizing such a novel dual-band balun, the practical ranges of the frequency ratio, terminated impedances, and two free variables are provided under the conventional microstrip fabrication constraints. By adopting four coupled-line sections, six transmission-line stubs, and an isolation resistor, a microstrip prototype balun working at 1.0/2.6 GHz is designed, fabricated, and measured. There is a good agreement between the simulated and measured results. The wide bandwidths of 290 MHz from 0.83 to 1.12 GHz and 270 MHz from 2.44 to 2.71 GHz are obtained with the measured return losses (|S 11 |, |S 22 |, |S 33 |) and the isolation (|S 23 |) better than 10 dB, which effectively confirm the proposed theoretical predictions.

An Active Marchand Balun and Its Application to a 24-GHz CMOS Mixer

Abstract: A fully integrated 24-GHz Gilbert-cell mixer incorporating two on-chip Marchand baluns to convert single-ended signals into differential signals is presented in this paper. One is a passive balun at local oscillator (LO) port to improve isolation between the LO and radio-frequency (RF) ports, and the other is an active balun at RF port to enhance the conversion gain (CG) of the down-conversion mixer. The active balun utilizes complementary cross-coupled pairs (CCPs) to compensate for its resistive losses. Moreover, the gate-to-source capacitances ( $C_{{\text {gs}}}$ ) of the CCPs are also absorbed into coupled lines and then reduce the chip size. The chip area of the active balun is about one quarter of the passive one. The mixer is designed and implemented in a 0.18- $\mu \text{m}$ CMOS technology, and its chip size is 0.38 mm2 including all testing pads. With a power consumption of 18.9 mW and an LO power of 0 dBm, the mixer exhibits a measured CG of 12.8 dB, an input $P_{{\mathrm {in,1~dB}}}$ of −14.5 dBm, and LO-RF isolations better than 43 dB.

Compact 6.5-28.5 GHz On-Chip Balun With Enhanced Inband Balance Responses

Abstract: In this letter, a miniaturized on-chip stacked-spiral-coupled (SSC) Marchand balun is proposed with wideband operation, i.e., fractional bandwidth (FBW) >125%. To improve the inband balance responses (i.e., amplitude- and phase-balances), the self-coupled compensation line and center-tapped ground-shield with deep trench are introduced. To verify the mechanism of structures mentioned above, a balun operating from 6.5-28.5 GHz is implemented and fabricated using a 0.13- $\mu {\mathrm { m}}$ SiGe technology. The measured amplitude- and phase-imbalances of the on-chip balun are ±1 dB and ±1.65°, respectively.

A W-Band Micromachined On-Wafer Probe With Integrated Balun for Characterization of Differential Circuits

Abstract: Differential circuits are commonly used for millimeter-wave monolithic integrated circuits such as amplifiers and voltage-controlled oscillators. The infrastructure for their characterization, however, remains limited at these frequencies. With the recent development in micromachined on-wafer probes, a probe integrated with balun circuitry can provide a convenient way to characterize differential integrated circuits. In this paper, a micromachined probe with an integrated balun operating at W-band is demonstrated. The measured S-parameters of the balun probe are in agreement with simulation and meet the design performance requirements. Furthermore, the balun probe design has the potential to be scaled to submillimeter-wave frequencies.

Dual-polarized vibrator unit, antenna and multi-frequency antenna array

Abstract: The invention provides a dual-polarized vibrator unit, an antenna and a multi-frequency antenna array. The dual-polarized vibrator unit includes a radiator and a balun support portion for feeding of the radiator. The radiator includes a dielectric substrate, two pairs of dipole antenna arms being disposed on an upper surface of the dielectric substrate and in orthogonal arrangement of plus or minus 45 degrees, and at least one coupling metal strap disposed on a lower surface of the dielectric substrate. Current induction is generated between the dipole antenna arms and the coupling metal strap so that a current path is formed on the coupling metal strap. The vibrator unit and the antenna thereof in the invention can achieve the ultra-broadband, high gain, high efficiency, high cross polarization ratio and high front-ratio, high isolation, low profile and low coupling and is simple and beautiful in structure, easy in engineering realization and suitable for mass production, the production cost is reduced, and the electrical performance index meets the base station antenna industry standard.

An extremely wideband tapered balun for application in tightly coupled arrays

Abstract: This paper presents the design of a single layer, compact, tapered balun with a >20:1 bandwidth and less than λ/17 in length at the lowest frequency of operation. The balun operates from 0.7GHz to over 15GHz. It can provide both impedance transformation as well as a balanced feed for tightly coupled arrays. Its performance is compared with that of a full-length balun operating over the same frequency band. There is a high degree of agreement between the two baluns.

High-Gain Linearly Tapered Antipodal Slot Antenna on LCP Substrate at E- and W-Bands

Abstract: In this letter, we present a high-gain linearly tapered antipodal slot antenna (LTASA) on a thin-film liquid crystal polymer (LCP) substrate for E- and W-band applications. The proposed LTASA consists of a microstrip (MS) line feed, an MS-to-antipodal parallel strip line (APSL) balun, a linearly flared antipodal slot line (ASL), and periodic corrugations. An ultrawideband of from 47 to 110 GHz was demonstrated by full-wave simulation and measurement. To characterize the far fields of the LTASA, we developed an optical far-field measurement system in which the RF signal captured by the LTASA will be upconverted to the optical spectrum for power detection. By utilizing the optical approach, the developed system addresses flexibility, light weight, low profile, and low interconnection loss. A high gain of $16.5 + 1 ~\hbox{dBi}$ , narrow beamwidth, low sidelobes, and low cross polarization were demonstrated for the proposed LTASA from 75 to 95 GHz.

Ultrawideband tightly coupled array for multiband communications at S-X frequencies

Abstract: In satellite-borne platforms where the reduction of size, weight and power are very critical design factors. To pursuing to this goal, we present a design for ultrawideband tightly coupled antenna array (TCDA) with wide angle scanning and low cross polarization. Although TCDAs possess the merit of wideband, wide-scanning performance, they need a balanced feeding structure which introduces several practical challenges. In this paper, we demonstrate a low-cost wideband integrated balun to incorporate with array and increase overall bandwidth. The final array is capable of working simultaneously on numerous communication bands, including S, C, and lower-X bands (2–10GHz). Besides, the array shows ±45° scanning in all planes, and less than − 15dB cross-polarization. To validate the design, an 8 × 8 TCDA prototype is fabricated and measured.

The Study and Design of a Miniaturized Microstrip Balun With a Wider Bandwidth

Abstract: In this letter, a miniaturized microstrip balun is presented. It replaces the half-wavelength open microstrip line in Marchand balun with a quarter-wavelength short microstrip line. Also, to improve the insertion loss, an I-shaped slot is etched in the ground. Finally, a rectangular slot is etched in the ground near port 2 to further eliminate the imbalance. The measured result shows that the bandwidth of the proposed balun for |S11| ≤ −10 dB is from 1.19 to 3.23 GHz, and the relative bandwidth is about 92.3%. In the operating band, the maximum amplitude and phase imbalance are 0.49 dB and 6.5°, respectively. The realized balun has a dimension of 17.5 × 18 mm2, equal to 0.1λg × 0.1λg (λg is the guided wavelength at 1.17 GHz, the lowest operating frequency).

Modified Wideband Marchand Balun With Tunable Power Division Ratio and Constant Phase

Abstract: A balun with a wide tunable power division ratio and constant phase across a wide frequency band is presented. The proposed design is a modification of the traditional Marchand balun with a varactor and series resistor loaded at the central point of the two connected pairs of coupled lines. The varactor is used to control the power division ratio at two output ports, whereas the resistor is used to stabilize the power division across a wide operational bandwidth. The achievable power division ratio and differential phase are investigated for different band ranges. A prototype is designed, fabricated, and tested. The results indicate a tuning power ratio range from 1:1 to 3.5:1 across 80% fractional bandwidth (1.2–2.8 GHz) with more than 10 dB return loss and less than 9 $^{\circ}$ differential phase.

A tunable gain and tunable band active balun LNA for IEEE 802.11ac WLAN receivers

Abstract: A tunable gain and tunable band low-noise amplifier (LNA) for IEEE 802.11ac WLAN standard is proposed, with low noise figure and high linearity. The LNA is based on an active balun cascode topology with buffered negative feedback to achieve a differential signalling at the output. The unique feature of the proposed LNA includes highly linear, continuously tunable gain from 3 dB to 23 dB, in addition to a tunable frequency band from 4.5 GHz to 5.5 GHz, while meeting other critical LNA parameters such as noise figure and third order input inter-modulation point (IIP3). Tunable gain is achieved with the help of active CMOS resistors (ACR) at the core LNA load and also in the active negative feedback path, while tunable frequency band is achieved by a tunable LC tank load. The buffered negative feedback with cascode active balun provides the low noise figure and competitive IIP3. The LNA is implemented in 1.2V, 65nm CMOS technology. Measured LNA performance shows a noise figure of 2 dB and IIP3 of −6.5dBm at the highest gain of 23 dB and a noise figure of 6 dB and IIP3 of +10dBm at the lowest gain of 3 dB. The active chip area of the LNA is 0.043mm2 with a moderate power consumption of 16mW.

A 100-nW Sensitive RF-to-DC CMOS Rectifier for Energy Harvesting Applications

Abstract: A 100-nW sensitive differential drive CMOS RF-DC converter implemented in a 0.18 µm technology is developed. The circuit is meant to be used as a bootstrap or start-up circuit in an energy harvesting application. The 66-stage rectifier is tapered for optimal performance. Driving a 10 MO load, the circuit has a measured output greater than 100 mV, for an input power of 100 nW at 350 MHz. For an input power of 100 µW at 350 MHz, the circuit is measured to have an output of 1.25 V, for an output load of 10 MO. Measurement results include balun and matching network losses. For infinite output resistive loads, the circuit is simulated to have an output greater than 1 V, for input powers larger than-30 dBm.

Broad-band dual polarization base station antenna unit

Abstract: The invention provides a broad-band dual polarization base station antenna unit which is used to solve problems that structural stability is poor and a technology is complex in an existing dual polarization base station antenna unit The unit comprises radiators (1), a first feed balun (2), a second feed balun (3), a pedestal (4) and a reflecting plate (5) The first feed balun (2) and the second feed balun (3) are mutually orthogonal Top ends of the two feed baluns (2, 3) are provided with the radiators (1) which are vertical to the top ends and bottom ends are connected to radio frequency cables (6) respectively The pedestal (4) is fixed to the reflecting plate (5) Tops and bottoms of the first feed balun (2) and the second feed balun (3) are provided with two rectangular embossments respectively and the rectangular embossments are used for connecting the radiators (1) and the pedestal (4) The unit possesses advantages that the structure is simple; processing is convenient; a frequency band is wide; an isolation degree is high and a directional diagram is good And the unit can be used for a miniaturization base station antenna in a new generation communication system